Highly Stable Colloidal “Giant” Quantum Dots Sensitized Solar Cells

Abstract

Colloidal quantum dots (QDs) are widely studied due to their promising optoelectronic properties. This study explores the application of specially designed and synthesized “giant” core/shell CdSe/(CdS)x QDs with variable CdS shell thickness, while keeping the core size at 1.65 nm, as a highly efficient and stable light harvester for QD sensitized solar cells (QDSCs). The comparative study demonstrates that the photovoltaic performance of QDSCs can be significantly enhanced by optimizing the CdS shell thickness. The highest photoconversion efficiency (PCE) of 3.01% is obtained at optimum CdS shell thickness ≈1.96 nm. To further improve the PCE and fully highlight the effect of core/shell QDs interface engineering, a CdSexS1−x interfacial alloyed layer is introduced between CdSe core and CdS shell. The resulting alloyed CdSe/(CdSexS1−x)5/(CdS)1 core/shell QD‐based QDSCs yield a maximum PCE of 6.86%, thanks to favorable stepwise electronic band alignment and improved electron transfer rate with the incorporation of CdSexS1−x interfacial layer with respect to CdSe/(CdS)6 core/shell. In addition, QDSCs based on “giant” core/CdS‐shell or alloyed core/shell QDs exhibit excellent long‐term stability with respect to bare CdSe‐based QDSCs. The giant core/shell QDs interface engineering methodology offers a new path to improve PCE and the long‐term stability of liquid junction QDSCs.

Zero‐Dimensional Perovskite Nanocrystals for Efficient Luminescent Solar Concentrators

“…To address the increasing demand of renewable energy, researchers have focused on new emerging optoelectronic devices using solar technologies, such as photovoltaic (PV) devices, solar‐driven water splitting, and luminescent solar concentrators (LSCs) . Among them, LSCs could serve as a large‐area sunlight collector for efficient solar‐to‐electricity conversion .…”

Tailoring the Heterostructure of Colloidal Quantum Dots for Ratiometric Optical Nanothermometry

“…[56,[78][79][80][81][82][83][84][85][86][87][88][89][90][91][92][93] Typically, when the temperature increases, the excitonic emission from QDs is redshifted and the nonradiative decay rates are increased, leading to the variation of both PL intensity and PL peak width. [60,63,75,94,95] Recent studies revealed many major factors affecting the temperaturedependent optical properties (PL intensity or lifetime), such as phonon-assisted thermal escape, activation/redistribution of carrier recombination centers with temperature, energy transfer (ET), etc. [96] The PL peak position is largely affected by the thermal expansion of the QD, which regulates dE/dT, where E is the bandgap energy and T is the absolute temperature.…”

Earth abundant colloidal carbon quantum dots for luminescent solar concentrators

“…quantum dot (QD) solar cells, perovskite solar cells, and dye solar cells]. [18][19][20][21][22][23][24] However the PCE and long-term stability of excitonic solar cells still have a lot of room to improve. During the last forty years, luminescent solar concentrator (LSC) technology has attracted a lot of attention as a solar-light harvester, which can significantly reduce the cost of electricity by decreasing the active area of silicon solar cells used for generating the same amount of power, if the PCE of the LSCs is higher than 6%.…”