Low-temperature grown TiO2 nanorods for MAPbI3 photovoltaics

Abstract

Fully low-temperature processed perovskite solar cell (PeSC) is fundamental to the development of flexible PeSC devices and perovskite tandem cells. Low-temperature grown TiO2 nanorods (NRs) have been proposed by hydrothermal method at ~ 150 °C, which are applied as electron selective layers (ESL) for PeSCs. The annealing temperature of TiO2 barrier layers has an important impact in the formation of TiO2 NRs. Oblique TiO2 NRs on TiO2 compact layers annealed at 150 °C (L-cpTiO2) are better for charge transport in PeSCs than that from 450 °C annealing. HCl etching of TiO2 NRs greatly improved the TiO2 NRs/MAPbI3 interface and the photovoltaic performances of TiO2 NRs based PeSCs. Severe defect states and nonradiative recombination at MAPbI3 /etched TiO2 NRs interface have been relieved. Fully low-temperature processed PeSC based on etched TiO2 NRs exhibits the efficiency of 18.32% and weak hysteresis. Fully low-temperature PeSC based on TiO2 NRs affords perovskite photovoltaics a new route to large-scale manufacturing.