Constructing High-Performance Solar Cells and Photodetectors with A Doping-free Polythiophene Hole Transport Material

Over the past decades, there has been a growing interest in solution-based solar cells and photodetectors. Hole transport materials (HTMs) have played a critical role in advancing these electronics. However, the development of low-cost and efficient HTMs has not been satisfactory. In this study, we propose the use of poly(3-pentylthiophene) (P3PT) as a dopant-free polymeric HTM for quantum dot (QD) and perovskite electronic devices. P3PT offers a simple, low-cost and versatile solution. Compared to the commonly used poly(3-hexylthiophene), P3PT exhibits reduced molecular aggregation and preferential face-on orientation. These properties greatly enhance hole transport in optoelectronic devices. As a result, the photovoltaic performance of QD/polythiophene solar cells improves from about 8.6% to 9.5%, while that of perovskite/polythiophene solar cells increases from about 16% to 18.8%. These values are the highest reported in their respective fields. In addition, the use of P3PT HTMs significantly improves the photodetection performance of QD and perovskite photodetectors by a factor of about 3. This indicates the great potential of P3PT in various emerging optoelectronic applications.