Author Archives: admin

  Christian Schwarz, Heinz Bässler, Irene Bauer, Jan-Moritz Koenen, Eduard Preis, Ullrich Scherf, and Anna Köhler Advanced Materials 24 (2012) 922–925 [DOI][PDF] Internal photocurrent quantum yields near 100% can be obtained from the separation of loosely bound geminate pairs when sufficiently large electric fields are applied to organic heterojunctions. The fields needed for complete electron–hole […]

  Christina Scharsich, Ruth H. Lohwasser, Michael Sommer, Udom Asawapirom, Ullrich Scherf, Mukundan Thelakkat, Dieter Neher, Anna Köhler J. Poly. Sci. B: Polymer Physics 50 (2012) 442–453 [DOI][PDF] Aggregate formation in poly(3-hexylthiophene) depends on molecular weight, solvent, and synthetic method. The interplay of these parameters thus largely controls device performance. In order to obtain a […]

  Anna Hayer, Tanguy Van Regemorter, Bianca Höfer, Chris S. K. Mak, David Beljonne, Anna Köhler J. Poly. Sci. B: Polymer 50 (2012) 361-369 [DOI][PDF] Although carbazole-containing copolymers are frequently used as hole-transporting host materials for polymer organic light-emitting diodes (OLEDs), they often suffer from the formation of undesired exciplexes when the OLED is operated. […]

  Christian Wißler M.A. (Hrsg.) Mediendienst Forschung Universität Bayreuth, 2011 – Nr. 40 // 26. Oktober 2011 [PDF] Lichtenergie in elektrischen Strom zu verwandeln ist die Funktion von Solarzellen, die damit eine zentrale Bedeutung für die Gewinnung und Nutzung erneuerbarer Energien haben. Einem Forschungsteam der Universität Bayreuth, der LMU München und der TU München ist […]

  Heinz Bässler, Anna Köhler Topics in Current Chemistry Volume 218, (2011) Springer-Verlag, Berlin Heidelberg [DOI][PDF] Charge transport in organic semiconductors is a timely subject. Today, organic semiconductors are already widely used commercially in Xerography. For display and lighting applications they are employed as light emitting diodes (LEDs or OLEDs) or transistors, and they are […]

  Daniel Herrmann, Sabrina Niesar, Christina Scharsich, Anna Köhler, Martin Stutzmann and Eberhard Riedle J. Am. Chem. Soc. 133 (2011) 18220-18233 [DOI][PDF] Despite the central role of light absorption and the subsequent generation of free charge carriers in organic and hybrid organic-inorganic photovoltaics, the precise process of this initial photoconversion is still debated. We employ […]

  S.T. Hoffmann, J.M. Koenen, U. Scherf, I. Bauer, P. Strohriegl, H. Bässler, A. Köhler J. Phys. Chem. B 115 (2011) 8417-8423 [DOI][PDF] We have studied the temperature dependence of phosphorescence (Ph) and delayed fluorescence (DF) in two series of poly(p-phenylene) derivatives within a temperature range from 10 to 300 K under quasi-stationary conditions. One […]

  R.Q. Albuquerque, C.C. Hofmann, J. Köhler, A. Köhler J. Phys. Chem. B 115 (2011) 8063-8070 [DOI][PDF] Organic semiconductor devices such as light-emitting diodes and solar cells frequently comprise a blend of molecular or polymeric materials. Consequently, resonant energy transfer between the components plays a major role in determining device performance. Energy transfer may take […]

  Pamela Schrögel, Ausra Tomkeviciene, Peter Strohriegl, Sebastian T. Hoffmann, Anna Köhler and Christian Lennartz J. Mat. Chem. 21 (2011) 2266-2273 [DOI][PDF] We report a series of CBP-derivatives with superior thermal and electronic properties for the use as host materials for blue electrophosphorescent organic light emitting diodes. We applied a systematic variation of the substitution […]

  ST Hoffmann, P Schrögel, M Rothmann, R Albuquerque, P Strohriegl and A Köhler J. Phys. Chem. B 115 (2011) 414-421 [DOI][PDF] Carbazole-based materials such as 4,4´-bis(N -carbazolyl)-2,2´-biphenyl (CBP) and its derivatives are frequently used as matrix materials for phosphorescent emitters in organic light emitting diodes (OLED)s. An essential requirement for such matrix materials is a […]

  A Köhler, H Bässler J. Mater. Chem. 21 (2011) 4003-4011 [DOI][PDF] Dexter-type triplet transfer is a phenomenon that is ubiquitous in the field of molecular electronics, and that takes place at the interface of chemistry, physics and biology. It may be considered as a correlated transfer of two charges, and thus, models originally developed […]

  ST Hoffmann, H Bässler, A Köhler J. Phys. Chem. B 114 (2010) 17037–17048 [DOI][PDF] Energetic disorder is manifested in the inhomogeneous broadening of optical transitions in π-conjugated organic materials, and it is a key parameter that controls the dynamics of charge and energy transfer in this promising class of amorphous semiconductors. In an endeavor […]

  ST Hoffmann, E Scheler,JM Koenen, M Forster, U Scherf, P Strohriegl,H Bässler, A Köhler Phys.Rev. B 81 (2010) 165208 [DOI][PDF] It is a general notion that, in organic semiconductors, the transport of electronic excitations, such as neutral excitons of singlet or triplet type and charge carriers, is controlled by both, polaron and disorder effects. […]

  MW Thesen, B Höfer, M Debeaux, S Janietz, A Wedel, A Köhler, HH Johannes, H Krueger J. Pol. Sc. A 48 (2010) 3417-3430 [DOI][PDF] A series of novel styrene derived monomers with triphenylamine-based units, and their polymers have been synthesized and compared with the well-known structure of polymer of N,N0-bis(3-methylphenyl)-N,N0-diphenylbenzidine with respect to their […]

  ST Hoffmann, H Bässler, JM Koenen, M Forster, U Scherf, E Scheler, P Strohriegl, A Köhler Phys. Rev. B 81 (2010) 115103 [DOI][PDF] We have employed quasicontinuous fluorescence and phosphorescence spectroscopy within a temperature range between 10 and 500 K to monitor the spectral diffusion of singlet and triplet excitons in a series of […]

  A Köhler, H Bässler Materials Science and Engineering R, (2009) 71-109 [DOI][PDF] Today’s technology is not possible without optoelectronic devices such as light-emitting diodes, transistors and solar cells. These basic units of modern electronic appliancesmay be made not only from traditional inorganic semiconductors, but also from organic semiconductors, i.e. hydrocarbonmolecules that combine semiconducting properties […]

  L Sudha Devi, MK Al-Suti, N Yhang, SJ Teat, L Male, HA, Sparkes, RP Rainthby, MS Khan, A Köhler Macromolecules 42 (2009) 1131-1141 [DOI][PDF] The synthesis and characterization of the thieno[3,2-b]thiophene and dithieno[3,2-b:2′,3′-d]thiophene containing platinum(II) poly-ynes and their molecular precursors is described and the electronic structure is established by absorption, luminescence and photoinduced absorption […]

  L Sudha Devi, MK Al-Suti, C. Dosche, MS Khan, RH Friend, A Köhler Phys. Rev. B 78 (2008) 045210 [DOI][PDF] Efficient triplet exciton emission has allowed improved operation of organic light-emitting diodes (LEDs). To enhance the device performance, it is necessary to understand what governs the motion of triplet excitons through the organic semiconductor. […]

  II Fishchuk, A Kadashchuk, L Sudha Devi, P Heremans, H Bässler, A Köhler Phys. Rev. B 78 (2008) 045211 [DOI][PDF] Motivated by experiments monitoring motion of triplet excitations in a conjugated polymer containing Pt-atoms in the main chain (see Paper I), a theoretical formalism for electronic transport has been developed. It considers the interplay […]

  E Aharon, S Breuer, F Jaiser, A Köhler, GL Frey Chem. Phys. Chem. 9 (2008) 1430-1436 [DOI][PDF] Photophysical processes in conjugated polymers are influenced by two competing effects: the extent of excited state delocalization along a chain, and the electronic interaction between chains. Experimentally, it is often difficult to separate the two because both […]

  C Schuetz, B Höfer, F Jaiser, H Krueger, M Thesen, S Janietz, A Köhler Physica status solidi B 245 (2008) 810-813 [DOI][PDF] Cascading energy transfer is a usually undesired effect in organic-host guest systems that are designed for light-emitting purposes. Here we demonstrate a chemical approach to suppressing undesired energy transfer from the blue […]

A Hayer, ALT Khan, RH Friend, A Köhler Phys. Rev. B 71 (2005) 241302 [DOI][PDF] Poly(9,9-dioctylfluorene) (PFO) is widely used as a highly efficient blue-emitting polymer for light-emitting diode applications. Films of PFO are known to contain a planar β-phase or a disordered glassy phase that affects the emission characteristics. We have studied the morphology […]

Ö Mermer, G Veeraraghavan, TL Francis, Y Sheng, DT Nguyen, M Wohlgenannt, A Köhler, MK Al-Suti, MS Khan Phys. Rev. B. 72 (2005) 205202 [DOI][PDF] Following the recent observation of large magnetoresistance at room temperature in polyfluorene sandwich devices, we have performed a comprehensive magnetoresistance study on a set of organic semiconductor sandwich devices made […]

CSK Mak, A Hayer, SI Pascu, SE Watkins, AB Holmes, A Köhler, RH Friend Chem. Commun., 37 (2005) 4708-4710 [DOI][PDF] The photo- and electroluminescence properties of a series of novel, heteroleptic, mer-cyclometallated iridiumcomplexes have been fine-tuned from green to blue by changing the substituents on the pyridyl ring of the phenylpyridyl ligand. The X-ray crystal […]

C. Yang, ZV Vardeny, A Köhler, M Wohlgenannt, MK Al-Suti, MS Khan Phys. Rev. B, 70 (2004) 241202 [DOI][PDF] It has been found in recent measurements that the singlet-to-triplet exciton ratio in organic light-emitting diodes (OLEDs) is larger than expected from spin degeneracy, and that singlet excitons form at a larger rate than triplets. We […]

A Köhler und D Beljonne Advanced Functional Materials, (Feature article), 14 (2004),11 [DOI][PDF] Electron–electron interactions in organic semiconductors split the lowest singlet and triplet states by the exchange energy, ?EST. Measurement of singlet and triplet emission spectra in a large number of conjugated polymers yield an almost constant ?EST value close to 0.7?eV. This is […]

ALT Khan, P Sreearunothai, LM Herz, MJ Banach, A Köhler Phys. Rev. B., 69 (2004) 085201 [DOI][PDF] We have performed a detailed study of the photoluminescence from thin films of blue-light-emitting poly(9,9-dioctylfluorene) containing different fractions of planarized (ß-phase) chains within the glassy polymer film. By choosing solvents with a range of polarities and boiling points […]

AJ Sandee, CK Williams, N Evans, JR Davies, CE Boothby, A Köhler, RH Friend and AB Holmes J. Am. Chem. Soc. 126 (2004) 7041-7048 [DOI][PDF] We report the synthesis and photophysical study of a series of solution-processible phosphorescent iridium complexes. These comprise bis-cyclometalated iridium units [Ir(ppy)2(acac)] or [Ir(btp)2(acac)] where ppy is 2-phenylpyridinato, btp is 2-(2‘-benzo[b]thienyl)pyridinato, […]

A Hayer, A Köhler, E Arisi, I Bergenti, A Dediu, C Taliani, M Al-Suti, MS Khan Synth. Met. 147, (2004) 155-158 [DOI][PDF] This study is concerned with the characterisation of the injection properties of the manganite compound La0.7Sr0.3MnO3 (LSMO) and its use as a spin-polarised anode in polymer light-emitting diodes. Charge carrier injection and electroluminescence […]

MS Khan, MRA Al-Mandhary, MK Al-Suti, FR Al-Battashi, S Al-Saadi, B Ahrens, JK Bjernemose, MF Mahon, PR Raithby, M Younus, N Chawdhury, A Köhler, EA Marseglia, E Tedesco, N Feeder, SJ Teat Dalton Trans., (15): 2377-2385 2004. [DOI][PDF] A series of protected and terminal dialkynes with extended p-conjugation through a condensed aromatic linker unit in […]

A Köhler and JS Wilson Organic electronics 4 (2003) 179 – special issue [DOI][PDF] The mechanism for the formation of singlet and triplet states in conjugated polymer-based light-emitting diodes (LEDs) is crucial in determining the overall efficiencies of these devices. If simple spin statistics apply then singlets and triplets should be formed in the ratio […]

MB Johnston, LM Herz, ALK Khan, A Köhler, AG Davies, EH Linfield Chem. Phys. Lett. 377 (2003), 256-262 [DOI][PDF] Following the recent observation of large magnetoresistance at room temperature in polyfluorene sandwich devices, we have performed a comprehensive magnetoresistance study on a set of organic semiconductor sandwich devices made from different π -conjugated polymers and […]

ALT Khan, MJ Banach and A Köhler Synth. Met., 139 (2003), 905-907 [DOI][PDF] In the blue light-emitting polymer poly(9,9-dioctylfluorene) (PFO) two distinct morphological phases have been identified, that is the glassy phase and a planar ß-phase. We show that the proportion of the formation of the two phases can be controlled by simply spinning thin […]

JS Wilson, RJ Wilson, RH Friend, MK Al-Suti, MRA Al-Mandhary, MS Khan, A Köhler Phys. Rev. B., 67 (2003) 125206 [DOI][PDF] We investigate the polarization of optical transitions associated with the singlet S1 and triplet T1 and Tn excited states in a uniaxially aligned platinum-containing conjugated polymer which contains a 2-methoxy-5-(´-ethyl)-hexyloxy (MEH)-substituted phenyl ring. For […]

PJ Brown, DS Thomas, A Köhler, JS Wilson, J-S Kim, CM Ramsdale, H Sirringhaus, RH Friend Phys. Rev. B., 67 (2003) 064203 [DOI][PDF] The absorption spectrum of polythiophene and its derivative poly(3-hexylthiophene) (P3HT) is usually described in terms of an intrachain exciton coupled to a single phonon mode. We show that this model is too […]

MS Khan, MK Al-Suti, MRA Al-Mandhary, B Ahrens, JK Bjernemose, MF Mahon, L Male, PR Raithby, J Wilson, RH Friend, A Köhler J. Chem. Soc., Dalton Trans., (2003) 65-73. [DOI][PDF] A new series of rigid rod protected and terminal dialkynes with extended p-conjugation through aromatic and hetero-aromatic linker units in the backbone, 2,5-bis(trimethylsilylethynyl)-1-(2-ethylhexyloxy)-4-methoxybenzene 1a, 2,5-bis(ethynyl)-1-(2-ethylhexyloxy)-4-methoxybenzene […]

MS Khan, MRA Al-Mandhary, MK Al-Suti, TC Corcoran, Y Al-Mahrooqi, JP Attfield, N Feeder, WIF David, K Shankland, RH Friend, A Köhler, EA Marseglia, E Tedesco, CCTang, PR Raithby, JC Collings, KP Roscoe, AS Batsanov, LM Stimson, TB Marder N. J. Chem. 27 (2003) 140-149 [DOI][PDF] A series of 1,4-diethynylbenzene (1) derivatives, H–C ≡ C–R–C […]

MS Khan, MRA Al-Mandhary, MK Al-Suti, B Ahrens, MF Mahon, L Male, PR Raithby, CE Boothby, A Köhler J. Chem. Soc., Dalton Trans., (2003) 74-84. [DOI][PDF] A series of trimethylsilyl-protected and terminal mono- and bis-alkynes based on 9,9-dioctylfluorene, 2-(trimethylsilylethynyl)-9,9-dioctylfluorene 1a, 2-ethynyl-9,9-dioctylfluorene 1b, 2,7-bis(trimethylsilylethynyl)-9,9-dioctylfluorene 2a, 2,7-bis(ethynyl)-9,9-dioctylfluorene 2b, have been synthesised. Reaction of trans-[(PnBu3)2PtCl2] with 2 equivalents […]

A Köhler, JS Wilson, RH Friend Adv. Mater. 14 (2002) 701-707 and Advanced Engineering Materials 4 (2002) 453-459. [DOI][PDF] Progress reports are a new type of article in Advanced Engineering Materials, dealing with the hottest current topics, and providing readers with a critically selected overview of important progress in these fields. It is not intended […]

A Köhler, JS Wilson, RH Friend, MK Al-Suti, MS Khan, A Gerhard, H Bässler J. Chem. Phys. 116 (2002) 9457-9463. [DOI][PDF] We have studied the evolution of the T1 triplet excited state in an extensive series of phenylene ethynylene polymers and monomers with platinum atoms in the polymer backbone and in an analogous series of […]

MS Khan, MRA Al-Mandhary, M Al-Suti, N Feeder, S Nahar, A Köhler, RH Friend, PJ Wilson, PR Raithby J. Chem. Soc., Dalton Trans. (2002) 2441-2448. [DOI][PDF] The synthesis and characterisation of a series of novel poly-yne polymers, trans-[–(PnBu3)2Pt(C ≡ C–L–C ≡ C)-]n (L = 2-(2′-thienyl)-pyridine (L1), 2,5-bis(2′-thienyl)pyridine (L2), 6,6′-bis(2?-thienyl)-3,3′-bipyridine (L3)), and the corresponding platinum dimers […]

MS Khan, MRA Al-Mandhary, MK Al-Suti, AK Hisahm, PR Raithby, B Ahrens, MF Mahon, L Male, EA Marseglia, E Tedesco, RH Friend, A Köhler, N Feeder, SJ Teat J. Chem. Soc., Dalton Trans. (2002) 1358-1368. [DOI][PDF] A series of trimethylsilyl-protected bis(ethynyl)oligopyridine derivatives Me3SiC ≡ C–R–C ≡ C–SiMe3 (R = 2,2′-bipyridine-5,5′-diyl (1a), 2,2′-bipyridine-6,6′-diyl (2a), 2,2′:6′,2?-terpyridine-6,6?-diyl (3a), […]

JS Wilson, AS Dhoot, AJAB Seeley, MS Khan, A Köhler, RH Friend Nature 413 (2001) 828-831. [DOI][PDF] The efficiency of light-emitting diodes (LEDs) made from organic semiconductors is determined by the fraction of injected electrons and holes that recombine to form emissive spin-singlet states rather than non-emissive spin-triplet states. If the process by which these […]

JS Wilson, N Chawdhury, MRA Al-Mandhary, M Younus, MS Khan, PR Raithby, A Köhler, RH Friend J. Am. Chem. Soc. 123 (2001) 9412-9417. [DOI][PDF] The energy gap law established for aromatic hydrocarbons and rare earth ions relates the nonradiative decay rate to the energy gap of a transition through a multiphonon emission process. We show […]

JS Wilson, A Köhler, RH Friend, MK Al-Suti, MRA Al-Mandhary, MS Khan, PR Raithby J. Chem. Phys. 113 (2000) 7627-7634. [DOI][PDF] By use of optical steady state and time resolved spectroscopy, we studied the evolution of the triplet excited state in a series of six ethynylenic polymers of the structure [-Pt(PBu3n)2 -C ≡ C-R-C ≡ […]

N Chawdhury, A Köhler, RH Friend, W-Y Wong, M Younus, PR Raithby, J Lewis, MRA Al-Mandhury, YC Corcoran, MS Khan J. Chem. Phys. 110 (1999) 4963-4970. [DOI][PDF] Soluble, rigid-rod organometallic polymers trans-[-Pt(PBu3n)2–C ≡ C–R–C ≡ C–]8 (R ≡ bithienyl 2, terthienyl 3) have been synthesized in good yields by the CuI-catalyzed dehydrohalogenation reaction of trans-[-Pt(PBu3n)2Cl2] […]

N Chauwdhury, A Köhler, MG Harrison, DH Hwang, AB Holmes, RH Friend Synth. Met. 102 (1999) 871-872. [DOI][PDF] Photocurrent (PC) and current-voltage measurements were taken on MEH-PPV [poly(2-methoxy-5-(2′-ethyl-hexyloxy)-paraphenylene vinylene] in an as-made photocell, ITO / MEH-PPV (265 nm) / Al, in the photocell under ambient air, under a mixture of oxygen + nitrogen, and in […]

A Köhler, M Younus, MRA Al-Mandhary, PR Raithby, MS Khan, RH Friend Synth. Met. 101 (1999) 246-247. [DOI][PDF] We compare the spectroscopic properties of donor-acceptor type poly-ynes of the type [D-C=C-A-C=C-]n with a fluorine-substituted phenylene or a thieno-pyrazine unit as acceptor, and platinum or alkoxy-substituted phenylene as donor. mehr…

A Köhler, DAd Santos, D Beljonne, Z Shuai, J-L Brédas, RH Friend, AB Holmes, A Kraus, K Müllen Nature 392 (1998) 903-906. [DOI][PDF] Conjugated polymers such as poly(p-phenylene vinylene)s (PPVs) allow low-cost fabrication of thin semiconducting films by solution processing onto substrates. Several polymeric optoelectronic devices have been developed in recent years, including field-effect transistors, […]

M Younus, A Köhler, S Cron, N Chawdhury, MRA Al-Mandhary, MS Khan, J Lewis, NJ Long, RH Friend, PR Raithby Angew. Chemie, Internat. Ed. 37 (1998) 3036-3039. [DOI][PDF] The smallest band gap observed so far (1.77 eV) for an organometallic polymer is exhibited by the blue, rigid-rod polymer 2, which is prepared by the reaction […]

N Chauwdhury, A Köhler, RH Friend, M Younus, NJ Long, PR Raithby, J Lewis Macromolecules 31 (1998) 722-727. [DOI][PDF] We have studied the dependence of intersystem crossing and the spatial extent of singlet and triplet excitons in platinum-containing poly-yne polymers with the general formula [Pt(PR3)2C ≡ CLC ≡ C]n (R = Et, nBu; L = […]

RH Friend, GJ Denton, JJM Halls, NT Harrisson, AB Holmes, A Köhler, A Lux, SC Moratti, K Pichler, N Tessler, K Towns, HF Wittmann Solid State Commun. 102 (1997) 249-258. [DOI][PDF] We report progress in the processing and application of poly(phenylene vinylene), PPV, as the emissive layer in electroluminescent diodes, LEDs. Photoluminescence efficiencies above 60% […]

A Köhler, DAd Santos, D Beljonne, Z Shuai, J-L Brédas, RH Friend, SC Moratti, AB Holmes Synth. Met. 84 (1997) 675-676. [DOI][PDF] We present photocurrent measurements of poly(p-phenylene vinylene) (PPV) and derivatives for photon energies up to 5.0 eV. We observe photocurrent peaks related to the first, second and third absorption peaks, which we associate […]

RH Friend, GJ Denton, JJM Halls, NT Harrisson, AB Holmes, A Köhler, A Lux, SC Moratti, K Pichler, N Tessler, K Towns, HF Wittmann Synth. Met. 84 (1997) 463-470. [DOI][PDF] We report progress in the processing and application of poly(phenylene vinylene), PPV, as the emissive layer in electroluminescent diodes, LEDs. Photoluminescence efficiencies above 60% for […]

D Beljonne, HF Wittmann, A Köhler, S Graham, M Younus, J Lewis, PR Raithby, MS Khan, RH Friend, JL Brédas J. Chem. Phys. 105 (1996) 3868-3877. [DOI][PDF] We present a joint experimental and theoretical investigation of the electronic excitations in transition metal-containing phenylene ethynylenes. The influence of the metal on the nature of the lowest […]

A Köhler, HF Wittmann, RH Friend, MS Khan, J Lewis Synth. Met. 77 (1996) 147-150. [DOI][PDF] We report photocurrent and photoluminescence measurements on blends of the organometallic polymer Pt-poly-yne and C60. Due to efficient intersystem crossing, triplet excitons with a binding energy of at least 0.8 eV are created after photoexcitation of Pt-poly-yne. We find […]

R Cervini, AB Holmes, SC Moratti, A Köhler, RH Friend Synth. Met. 76 (1996) 169-171. [DOI][PDF] Results are presented which explore the synthesis, characterization and photoluminescence of new types of conjugated copolymers which incorporate fused thiophene units. Such materials possess intense purple-red colours and some absorb in the near-infrared. The redox processes showed that the […]

A Köhler, J Gruener, RH Friend, K Müllen, U Scherf Chem. Phys. Lett. 243 (1995) 456-461. [DOI][PDF] We report measurements of the photovoltaic effect on single layer devices made with a ladder-type poly-(paraphenylene) (LPPP). Besides the photocurrent in the blue spectral range associated with p to p* intra-chain absorption we observe an additional response in […]

A Köhler, HF Wittmann, RH Friend, MS Khan, J Lewis Synth. Met. 67 (1994) 245-249 [DOI] We have carried out measurements of the photovoltaic effect in a platinum-containing poly-yne. A photocell was fabricated with the platinum poly-yne sandwiched between indium-tin oxide (ITO) and aluminium electrodes. A strong photoresponse was seen at the threshold of the […]