Boosting Power Conversion Efficiency of Quantum Dot-Sensitized Solar Cells by Integrating Concentrating Photovoltaic Concept with Double Photoanodes

Abstract

Despite great efforts dedicated to enhance power conversion efficiency (PCE) of quantum dot-sensitized solar cells (QDSSCs) in the past two decades, the efficiency of QDSSCs is still far behind its theoretical value. The present approaches for improving PCE are mainly focused on tailoring the bandgap of QDs to broadening light-harvesting and optimizing interfaces of component parts. Herein, a new solar cell architecture is proposed by integrating concentrating solar cell (CPV) concept into QDSSCs with double photoanode design. The Cu2S mesh is used as a counter electrode and sandwiched between two photoanodes. This designed battery structure can increase the PCE by 260% compared with a single photoanode. With the most extensively used CdS/CdSe QD sensitizers, a champion PCE of 8.28% (Voc = 0.629 V, Jsc = 32.247 mA cm−2) was achieved. This is mainly due to the increase in Jsc due to the double photoanode design and adoption of the CPV concept. In addition, another reason is that concentrated sunshine illumination induced a photothermal effect, accelerating the preceding chemical reactions associated with the conversion of polysulfide species. The cell fabrication and design reported here provides a new insight for further development of QDSSCs.

Black TiO2-Based Dual Photoanodes Boost the Efficiency of Quantum Dot-Sensitized Solar Cells to 11.7%

“…Furthermore, the radii of the second circles of the black TiO 2 based photoanodes are remarkably smaller than those of the pristine TiO 2 , corresponding to the smaller charge transfer resistance, which indicates that the charge transport of black TiO 2 -based devices is faster than that of pristine TiO 2 -based photoanodes. This is due to oxygen vacancy doping providing a more convenient transport channel for electrons [ 8 , 35 ]. This greatly improves the ability of the TiO 2 thin film to separate, collect, and transport photogenerated carriers in the cell, thereby reducing the loss of the photogenerated carriers during the device operation.…”

g-C3N4@TiO2 photoanodes for high-efficiency QDSSCs: improved electron transfer and photochemical stability

“…22,23 Therefore, there is still a long way to go to improve the photoelectric performance of QDSSCs by further optimizing their components. In QDSSCs, the photoanode, as an important part, provides the attachment site for quantum dots and a fast channel for photogenerated carriers to transfer to the external circuit, 24–26 so the photoanode plays an irreplaceable role. As shown in Table S1,† researchers have achieved better research results by selecting or optimizing different photoanodes in previous studies.…”

Cu-mediated broadening of the absorption band of quaternary Cu–Ag–In–S/CdSe type-II core/shell quantum dot-sensitized solar cells with an efficiency of 12.51% under 0.25 sun

“…Several studies adopting this strategy have demonstrated improved PCEs, such as CdSe 0.2 S 0.8 /CdMnSe, 11 CdS/InSb, 12 CuInSe 2 /Mg–CdS, 13 and CdS/CdSe. 14 In the alloying strategy, the bandgap can be tailored by adjusting the compositions of the constituent cation or anion elements separately (cation or anion alloying) or in combination (combined cation/anion alloying). Many studies have demonstrated the effectiveness of alloying in enhancing the photovoltaic performance of QDSSCs.…”