Effect of Multidonor and Insertion Position of a Chromophore on the Photovoltaic Properties of Phenoxazine Dyes

Abstract

Research and development of new organic semiconductor materials can never be terminated because any structural fine-tuning may result in an important impact on its application performance, although the effect may be negative in many cases. Herein, we designed and synthesized a series of phenoxazine-based dyes, YH1 , YH2 , YH3 , and YH4 , whose absorption spectrum, electrochemical cyclic voltammetry, theoretical calculation, dye-sensitized solar cell photovoltaic characteristics, and electrochemical AC impedance are used to analyze the photophysical, electrochemical, and photovoltaic performance of the materials, aiming to study the effect of multidonor and adjustment of the chromophore insertion position on their photovoltaic performance. When donor triphenylamine is added at the end of YH1 and YH3 , the absorption spectrum and photovoltaic performance of dyes YH2 and YH4 improved a little. The improvement is much greater when the chromophore (ethylenedioxy)thiophene in YH1 and YH2 is adjusted and inserted on the other side of phenoxazine and the energy conversion efficiencies (photon-to-current conversion efficiency) of the resulting dyes YH3 and YH4 reach 8.02 and 8.97%, respectively, which are 23 and 25% higher than those of YH1 and YH2 , respectively. Although the improvement may be because of factors such as the dihedral angle, the result will undoubtedly provide some reference for the future study of the relationship between the structure and performance of organic dyes.

Push‐Pull Phenoxazine‐Based Sensitizers for p‐Type DSSCs: Effect of Acceptor Units on Photovoltaic Performance

“…This property is particularly relevant in the context of p‐DSSC, which is strongly limited by charge recombination because (i) hole injection from triplet excited state could promote the formation of triplet charge‐separated state possibly longer‐lived than its singlet counterpart, and (ii) the long lifetime of the sensitizer in triplet excited state could leverage long‐distance hole injection in NiO and thus simultaneously delay charge recombination [31–34] . Further, the nitrogen atom in the system can be easily substituted with a bulky long branched alkyl chain, which not only suppresses the electron–hole recombination but also diminishes the aggregation as well as solubility problems, eventually leading to improved open‐circuit voltage ( V OC ) [35,36] . These features make phenoxazine a promising building block to develop sensitizers for p‐DSSC application.…”

“…[31][32][33][34] Further, the nitrogen atom in the system can be easily substituted with a bulky long branched alkyl chain, which not only suppresses the electron-hole recombination but also diminishes the aggregation as well as solubility problems, eventually leading to improved open-circuit voltage (V OC ). [35,36] These features make phenoxazine a promising building block to develop sensitizers for p-DSSC application. To the best of our knowledge, there are no literatures reports available on phenoxazine-based organic chromophores to explore their potential as p-type sensitizers in NiO-based p-DSSCs.…”

Comparative Studies on the Structure–Performance Relationships of Phenothiazine-Based Organic Dyes for Dye-Sensitized Solar Cells

“…Novel and highly efficient dyes play a decisive role in developing efficient DSSCs. Since the pioneering work of Grätzel, numerous researchers have done a lot of research work in dye development. − At present, thousands of dyes have been applied to DSSCs, mainly concentrated in porphyrin, − ruthenium complexes, , and metal-free pure organic dyes. − As early as in 2015, Kakiage et al reported a fantastic photoelectric conversion efficiency (PCE) of 14.34% using co-sensitization of silyl-anchor-based organic dye (ADEKA-1) and carboxy-anchor-based organic dye (LEG-4) . In 2019, Sun et al designed and synthesized organic dye ZL003, which achieved a relatively high PCE of 13.6% due to minimal energy losses on molecular excitation .…”

Novel D–A−π–A Organic Dyes with Phenoxazine as a Donor Unit for Dye-Sensitized Solar Cells: The Effect of an Ethynyl Group on Performance

“…Therein, the phenoxazine unit possesses excellent electron donor capacity due to its heterocyclic and 3D butterfly structure comprising electron-rich N and O heteroatoms. 28,29 In addition, its structure prevents molecular aggregation and benefits the hole transport abilities. Besides, it contains multiple active sites, which provides unlimited ideas for the design and synthesis of diversified new electronic units.…”

“…To date, various kinds of electron-rich units including aromatic amine, indole, carbazole, phenothiazine, phenoxazine, and so on − have been reported. Therein, the phenoxazine unit possesses excellent electron donor capacity due to its heterocyclic and 3D butterfly structure comprising electron-rich N and O heteroatoms. , In addition, its structure prevents molecular aggregation and benefits the hole transport abilities. Besides, it contains multiple active sites, which provides unlimited ideas for the design and synthesis of diversified new electronic units. − Sun et al designed and synthesized a series of novel phenoxazine-based dyes and achieved satisfactory photoelectric conversion efficiency. ,,− Moreover, our group has also carried out extensive research on POZ-based metal-free organic DSSC, ,− and applied it as a D unit to porphyrin dyes for the first time and achieved excellent performance .…”