High Efficiency Solution Processed Sintered CdTe Nanocrystal Solar Cells: The Role of Interfaces

Abstract

Solution processing of photovoltaic semiconducting layers offers the potential for drastic cost reduction through improved materials utilization and high device throughput. One compelling solution-based processing strategy utilizes semiconductor layers produced by sintering nanocrystals into large-grain semiconductors at relatively low temperatures. Using n-ZnO/p-CdTe as a model system, we fabricate sintered CdTe nanocrystal solar cells processed at 350 °C with power conversion efficiencies (PCE) as high as 12.3%. JSC of over 25 mA cm(-2) are achieved, which are comparable or higher than those achieved using traditional, close-space sublimated CdTe. We find that the VOC can be substantially increased by applying forward bias for short periods of time. Capacitance measurements as well as intensity- and temperature-dependent analysis indicate that the increased VOC is likely due to relaxation of an energetic barrier at the ITO/CdTe interface.

Recent Progress on Solution-Processed CdTe Nanocrystals Solar Cells

“…More recently, Panthani and co-workers [39,40] adopted this layer-by-layer technique to fabricate CdTe NC solar cells with a structure of ITO/CdTe/ZnO/Al. To find out the effect of ZnO on the performance of solar cell devices, they prepared ZnO thin film by using a ZnO NC solution or a sol-gel In-doped ZnO.…”

“…More recently, Panthani and co-workers [39,40] adopted this layer-by-layer technique to fabricate CdTe NC solar cells with a structure of ITO/CdTe/ZnO/Al.…”

STRUCTURAL AND OPTICAL PROPERTIES OF CdTe THIN FILMS OBTAINED BY ELECTRODEPOSITION

“…CdTe in the shape of thin film can be polycrystalline or nanocrystalline, which can contribute towards the change of its characteristics [4]- [6]. Different methods are used for the preparation of thin films of CdTe, including electrodeposition [4], [7], [8], magnetron sputtering [9], [10], thermal evaporation [5], [11], close space sublimation [12] - [14] and others [15], [16].…”

High‐Efficiency Photovoltaic Conversion at Selective Electron Tunneling Heterointerfaces

“…[12][13][14][15] Therefore, interface engineering was widely applied to control the photoinduced charge transport processes at the heterointerface for improving the performance of photovoltaic devices. [16][17][18][19] Recently, we discovered an ipsilateral selective electron tunneling (ISET) mechanism, which can be used to effectively separate photoinduced electron-hole pair at the heterointerface. [20,21] Specifically, when photoactive materials are assembled on the outside surface of single-layer graphene (SLG)/TiO 2 , Schottky diode, photoexcited electrons, as well as holes produced from the photoactive materials transport along the same direction to SLG, whereas only electron can further inject into the TiO 2 layer, thus realizing photogenerated electron-hole pair separation at the Schottky interface.…”