Perovskite solar cells (PSCs) have shown a significant improvement in power conversion efficiency (PCE) in the last few years. However, instability of PSCs is still a barrier for successful industrialization. In particular, spiro-OMeTAD with additives, despite a popular choice for hole transport material (HTM) in PSCs, is one of the causes for device thermal instability. In this work, one of additives in HTM, 4-tert-butylpyridine (tBP) is proved to be a factor of device instability under thermal treatment. Simple solution engineering which excludes the use of tBP in the HTM results in better device stability. The origin of thermal stability improvement shown in this work is attributed to the suppression of morphological change of HTM. Further researches towards thermal stability of perovskite material and dopant-free HTM should be essential since tBP removal was not able to solve the thermal stability issue.
- Perovskite solar cells
- Thermal stability