Progress and Future Potential of All-Small-Molecule Organic Solar Cells Based on the Benzodithiophene Donor Material

Abstract

Organic solar cells have obtained a prodigious amount of attention in photovoltaic research due to their unique features of light weight, low cost, eco-friendliness, and semitransparency. A rising trend in this field is the development of all-small-molecules organic solar cells (ASM-OSCs) due to their merits of excellent batch-to-batch reproducibility, well-defined structures, and simple purification. Among the numerous organic photovoltaic (OPV) materials, benzodithiophene (BDT)-based small molecules have come to the fore in achieving outstanding power conversion efficiency (PCE) and breaking the 17% efficiency barrier in single-junction OPV devices, indicating the significant potential of this class of materials in commercial photovoltaic applications. This review specially focuses on up-to-date information about improvements in BDT-based ASM-OSCs since 2011 and provides an outlook on the most significant challenges that remain in the field. We believe there will be more exciting BDT-based photovoltaic materials and devices developed in the near future.

Recent Progress in Semitransparent Organic Solar Cells: Photoabsorbent Materials and Design Strategies

“…The Shockley-Queisser (SQ) limit for the PCE of a single-junction opaque OSC is 33.1%, while 20.6% for an ST-OSC with an AVT of 100% [41]. Small molecules emerge as competitively feasible to their polymer counterparts because of several advantages, such as less batch-to-batch variation, easier energy level control, defined molecular weight, and ascertainable structure-property relationships with optoelectronic properties [42,43]. The advent of ITIC-and Y6-based NFA materials in 2015 and 2019, respectively, resulted in rapid progress in fused ring electron acceptors (FREAs) with NIR absorption and offered a new opening to achieve a good balance between the PCE and transparency of ST-OSCs [44,45].…”

Ternary Organic Solar Cells by Small Amount of Efficient Light Absorption Polymer PSEHTT as Third Component Materials

“…While incorporating third component materials into binary films, it is inevitable to introduce charge traps at the D/A interface due to the lowest unoccupied molecular orbital (LUMO) energy level barriers of the two acceptors or highest occupied molecular orbital (HOMO) energy level barriers of the two donors [15,16]. The cascade LUMO energy levels or HOMO energy levels of the relevant materials should be taken into consideration to avoid forming deep charge traps [17,18].…”