Solution‐Processed TiO 2 Nanoparticles as the Window Layer for CuIn(S,Se) 2 Devices
2012; Wiley; Volume: 2; Issue: 11 Linguagem: Inglês
10.1002/aenm.201200115
ISSN1614-6840
AutoresHuanping Zhou, Tze‐Bin Song, Choong‐Heui Chung, Lei Bao, Brion Bob, Rui Zhu, Hsin‐Sheng Duan, Chia‐Jung Hsu, Yang Yang,
Tópico(s)TiO2 Photocatalysis and Solar Cells
ResumoAbstract As a wide‐bandgap semiconductor, titanium dioxide (TiO 2 ) with a porous structure has proven useful in dye‐sensitized solar cells, but its application in low‐cost, high‐efficiency inorganic photovoltaic devices based on materials such as Cu(InGa)Se 2 or Cu 2 ZnSnS 4 is limited. Here, a thin film made from solution‐processed TiO 2 nanocrystals is demonstrated as an alternative to intrinsic zinc oxide (i‐ZnO) as the window layer of CuInS x Se 1− x solar cells. The as‐synthesized, well‐dispersed, 6 nm TiO 2 nanocrystals are assembled into thin films with controllable thicknesses of 40, 80, and 160 nm. The TiO 2 nanocrystal films with thicknesses of 40 and 80 nm exhibit conversion efficiencies (6.2% and 6.33%, respectively) that are comparable to that of a layer of the typical sputtered i‐ZnO (6.42%). The conversion efficiency of the devices with a TiO 2 thickness of 160 nm decreases to 2.2%, owing to the large series resistance. A 9‐hour reaction time leads to aggregated nanoparticles with a much‐lower efficiency (2%) than that of the well‐dispersed TiO 2 nanoparticles prepared using a 15‐hour reaction time. Under optimized conditions, the champion TiO 2 nanocrystal‐film‐based device shows even higher efficiency (9.2%) than a control device employing a typical i‐ZnO film (8.6%).
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