The instability of colloidal lead halide perovskite nanocrystals (NCs) presents a significant challenge for their application in optoelectronic devices. This review examines the primary causes of instability in these NCs and the proposed mechanisms of degradation. It also introduces the recently developed synthesis and surface passivation methods to address the instability issue of colloidal perovskite NCs. Specifically, we focus on the various types of ligands and precursors introduced during NC synthesis or post-treatment and how they impact the structural and optical properties of the perovskite NCs. This review also proposes a systematic approach to evaluating stability enhancement strategies by establishing key parameters and ranking them based on working and processing conditions. Finally, we discuss the issues that need to be addressed in future research to achieve practical application of lead halide perovskite NCs in advanced optoelectronic systems.

The inclusion of inorganic nanoparticles in biological environments has led to the creation of hybrid nanosystems that are employed in a variety of applications. One such system includes quantum dots (QDs) coupled with the photoactive protein, bacteriorhodopsin (BR), which has been explored in developing enhanced photovoltaic devices. In this work, we have discovered that the kinetics of the BR photocycle can be manipulated using CdSe/CdS (core/shell) QDs. The photocycle lifetime of protein samples with varying QD amounts were monitored using time-resolved absorption spectroscopy. Concentration-dependent elongations of the bR and M state lifetimes were observed in the kinetic traces, thus suggesting that excitonic coupling occurs between BR and QDs. We propose that the pairing of BR with QDs has the potential to be utilized in protein-based computing applications, specifically for real-time holographic processors, which depend on the temporal dynamics of the bR and M photointermediates.