Low-temperature processable Sn-doped ZnO films as electron transporting layers for perovskite solar cells

Charge-transporting processable layers at a low temperature is a challenge for fabricating novel, highly stable and flexible optoelectronic devices. In fact, the crystallization of metal oxide usually needs to be processed under a high-temperature to obtain excellent semiconducting properties. In this work, Sn-doped ZnO (TZO) thin films, as electron transporting layers (ETLs) in perovskite solar cells, were prepared via sol-gel method at a temperature of less than 180 degrees C. The effects of annealing temperature on the properties of TZO thin films were investigated. It was found that the electrical properties of the TZO films were improved with increasing annealing temperature. In addition, an elemental composition analysis revealed that a temperature of only 140 degrees C sufficed for converting the precursor gel film into TZO film. The perovskite solar cell, which utilized a low-temperature TZO thin film, yielded a better power conversion efficiency than one with high-temperature ETLs (180 degrees C). These results imply that discovering low-temperature ETL processing for sol-gel enables good-quality metal oxide ETL, which can also be used in flexible solar cell applications.

Automated summary

This study successfully prepared low-temperature Sn-doped zinc oxide (TZO) thin films as electron transporting layers for perovskite solar cells, showing improved electrical properties with increasing annealing temperature. Element composition analysis revealed that a temperature as low as 140 degrees Celsius was sufficient for converting precursor gel film into TZO film. The perovskite solar cell utilizing low-temperature TZO thin film demonstrated higher power conversion efficiency compared to high-temperature ETLs.