Synthesis of highly dispersed TiO2 NPs/GO composites sol and its application in inverted perovskite solar cells

Abstract

The poor dispersion property and agglomerate of TiO 2 /graphene oxide (GO) composites greatly limit its application in optoelectronic devices. Here, low-temperature processed, high dispersion TiO 2 nanoparticles/GO (TiO 2 NPs/GO) sol was synthesized via modified sol-gel strategy combing by a hydrothermal process. The formation mechanism of TiO 2 NPs/GO sol is investigated and the results show that the TiO 2 NPs can be embedded to GO sheet with Ti–O–C chemical bond via dehydration condensation reaction between the hydroxyl groups on the surfaces of them. In addition, there are charge transportation between TiO 2 NPs and GO is confirmed, which benefits to enhance the charge transport efficiency of TiO 2 NPs. Using TiO 2 NPs/GO composite as cathode interface, the energy barrier of cathode interface is eliminated, and the hysteresis effect is largely suppressed. The highest power conversion efficiency (PCE) of 17.73% is achieved with TiO 2 NPs/GO, and the average PCE is also enhanced by 14.71% comparing to the control devices. This simple strategy light on the preparation high dispersive TiO 2 NPs/GO composites and correspondingly applied in inverted PSCs to enhance the interface contact. • Low-temperature processed, high dispersive TiO 2 NPs/GO composite sol has been synthesized. • The interface energy barrier and hysteresis are eliminated with TiO 2 NPs/GO interface modification. • The highest power conversion efficiency (PCE) of 17.73% is achieved.