Quantum Dot Antennae for Photovoltaics

The low-cost third-generation photovoltaic devices with semiconductor quantum dot (QD) absorbers are becoming popular due to the QDs having band gap tunability, high absorption coefficient, solution processability, multiple exciton generation and stability.^1-8 Nonetheless owing to the inherent drawback of abundant surface trap states in QDs, the propensity of interfacial charge recombination have always limited their power conversion efficiencies (PCE). In spite of such challenges, QD sensitized solar cells (QDSSCs) have emerged as the newest technology in the NREL chart and CsPbI₃ happen to be the new QD leader in 2017 with PCE of 13.4%. This lecture at first will discuss our efforts to improve the photoanode performance of liquid junction QDSSCs with core-shell II-VI and I-III-VI QD absorbers,^4-6 along with the counter electrode strategies.⁷ The second part of this lecture will deal with few of our approaches to fabricate relatively stable all-inorganic lead perovskite QD sensitized solar cells.^9,10 Our approach has been validated by transient absorption spectroscopy which shows lesser abundance of trap states and enhanced charge carrier recombination lifetime.