Metal halide-based perovskite quantum dots (QDs) have emerged as promising materials for optoelectronics and future energy applications. Among them, cesium lead halide-based perovskite quantum dots (Cs-LHQDs) have been found to be potential luminescent candidates and alternatives for the II–VI and $I−III−VI2$ groups semiconductor nanoparticles. These perovskites provide an excellent quantum yield (90%) larger than any other semiconductor QDs. At present, synthesis of Cs-LHQDs has been successfully achieved through a traditional colloidal-based hot-injection method and a room temperature precipitation method. Some of the interesting results in their structural, optical, and morphological properties are being analyzed to understand their energy-transfer mechanism in the colloidal state. Morphology of nanoplates, nanowires, nanocube, and nanosheets in these materials confirms their physical parameters-dependent self-assembly nature in a colloidal medium. Their potential use for light emitting diodes, photodetectors, and lasers is also highly motivated. This review provides a collective view of recent developments made in the synthesis of Cs-LHQDs and their properties.

Novel materials for third generation solar cells have emerged as one of the major scientific contribution in alternative energy approaches. In this scenario, semiconductor nanomaterials and organic dye molecules have greatly acknowledged for their vast contribution to the solar energy applications. Research on semiconductor nanomaterials for fabricating future generation solar cells is still fascinating due to their extraordinary structural and optical properties. Moreover, functionalization of organic dye molecules helps to harvest large amount of photons in order to apply them for high efficiency solar cell devices. Various attempts have been made to improve efficiency of quantum dot-sensitized solar cells and dye-sensitized solar cells using semiconductor inorganic nanomaterials and organic/organometallic dye molecules. Out of these, co-sensitization has been looking as most promising approach to improve the efficiency considerably. A record of over 14% of efficiency has been achieved in recent years through co-sensitization strategy. The energy transfer process during co-sensitization is also a very crucial and interesting. This review deals about materials, methods, various approaches and role of co-sensitization in enhancing the efficiency of dye-sensitized and quantum dot sensitized solar cells. The critical issues existing in the co-sensitization approach are also elaborately discussed.

Nanocrystals surface chemistry engineering offers a direct approach to tune charge carrier dynamics in nanocrystals-based photodetectors. For this purpose, we have investigated the effects of altering the surface chemistry of thin films of CsPbBr₃ perovskite nanocrystals produced by the doctor blading technique, via solid state ligand-exchange using 3-mercaptopropionic acid (MPA). The electrical and electro-optical properties of photovoltaic and photoconductor devices were improved after the MPA ligand exchange, mainly because of a mobility increase up to 5 × 10⁻³ ${\mathrm{cm}}^2/\mathrm{Vs}$ . The same technology was developed to build a tandem photovoltaic device based on a bilayer of PbS quantum dots (QDs) and CsPbBr₃ perovskite nanocrystals. Here, the ligand exchange was successfully carried out in a single step after the deposition of these two layers. The photodetector device showed responsivities around 40 and 20 mA/W at visible and near infrared wavelengths, respectively. This strategy can be of interest for future visible-NIR cameras, optical sensors, or receivers in photonic devices for future Internet-of-Things technology.