The influence of perovskite layer and hole transport material on the temperature stability about perovskite solar cells

Organometal halide perovskite has recently emerged as a promising solar cell material. However, the instability of perovskite solar cells when exposed to moisture, light, oxygen, UV and temperature remains a key challenge to the commercialization. Among these factors, temperature instability has been a major obstacle to fabricating the long-term operational device. In this study, we tried to explore the effect of perovskite layer and hole transport material on the temperature stability of solar cell at different three temperatures (20, 60 and 85 °C). The thermogravimetric analysis and absorption intensity variation characterization results on the perovskite layer indicated that the perovskite layer is not the main factor that leading to the temperature instability. Furthermore, temperature-dependent X-ray diffraction measurements indicated that the temperature has no remarkable effect on the crystal structure of perovskite materials. We also performed an aging test of the device by removing additives from spiro-OMeTAD HTM and the solar cells exhibited an improvement of temperature resistant, but it did not solve the problem of temperature instability. Finally, by using P3HT without additives to replace spiro-OMeTAD as HTM, we achieved the devices which can remain initial PCE after 800 h at 20, 60 and 85 °C and display outstanding temperature resistant. These findings demonstrated that the temperature instability of perovskite solar cells is mainly affected by HTM and additive, not the perovskite layer.