‘V’ Shape A–D–A‐Type Designed Small Hole Conductors for Efficient Indoor and Outdoor Staging from Solid Dye‐Sensitized Solar Cells and Perovskite Solar Cells

Abstract

With the exploration of new building blocks, a series of small organic hole transporting materials (SOHTMs) are designed and synthesized through simple microwave irradiation and systematically investigated in solid‐state dye‐sensitized solar cells (ss‐DSCs) and perovskite solar cells (PSCs). These V‐shaped SOHTMs having A–D–A architecture are endowed with low cost, better thermal stability, and good optical and electrochemical property, which respond to low indoor light and 1 sun illumination. The SOHTMs contain dibenzothiophene (DBT) and dibenzofuran (DBF) as core donors substituted with heteroaromatic molecules like naphthalene and indole, which are coded as SPH 1–SPH 4. ss‐DSCs and PSCs with SPH 4 (with LiTFSI) as SOHTMs exhibited a power conversion efficiency (PCE) amounting to 5.2% and 15.4%, respectively, under 1 sun illumination. Moreover, the applications of ss‐DSCs and PSCs in indoor environments are studied. Due to the good match with the indoor light emitting diode (LED) source, SPH 4 delivered PCEs of 26.3% (for ss‐DSCs) and 23.9 % (for PSCs) under 1800 lux illumination, which are very close to the PCE values obtained for standard hole transporting materials (HTMs) like spiro‐OMeTAD. Thus, these new SOHTMs provide the ultimate solution for the fabrication of photovoltaic devices, resulting in superior PCE under indoor light.

Improvement in Dibenzofuran-Based Hole Transport Materials for Flexible Perovskite Solar Cells

“…The development of oligomer HTMs has facilitated the learning of the structure–properties relationship of materials, which in turn, leads to a more accurate design of efficient and cost-effective HTMs. In this work, p-methoxyaniline-substituted dibenzofuran was introduced into oligomer HTMs due to the good planarity, flexible molecular structure design, and high thermal stability of dibenzofuran [ 17 , 18 , 19 ]. Bis(4-methoxyphenyl) amine was selected as an end group of the HTMs, which can accelerate hole transport because of its ability to enhance molecular coplanarity and intramolecular charge delocalization [ 20 , 21 ].…”

Recent Strategies for High-Performing Indoor Perovskite Photovoltaics

“…Other studies explored new materials to enhance hole extraction in Id-PPVs, which are novel donor–acceptor–donor molecule (D-A-D) 2,3-bis(4′-(bis(4-methoxyphenyl)amino)-[1,1′-biphenyl]-4-yl)fumaronitrile (TPA-BPFN-TPA) [ 81 ], dopant-free polymer PDTDT [ 59 ], an innovative graft-type polymer consisting of a dibenzothiophene-based conjugated backbone [ 51 ], a “V” shaped of A-D-A small organic HTL [ 82 ], and a unique new dopant of nicotinamide into PEDOT:PSS [ 83 ]. Poly(triaryl amine) was modified with hydrophobic poly(3-hexylthiophene) (P3HT) to adjust the interaction between the HTL and the undercoordinated Pb 2+ , improving the physical properties and hole extraction features [ 37 ], as shown in Figure 3 b. Consequently, a very high PCE of 39.2% was achieved under 1000 lx of LED illumination, with both V oc and J sc improvements.…”

Perovskite Photovoltaics for Artificial Light Harvesting

“…Later, Prasad et al [69] explored a series of V-shaped AÀ DÀ A small molecules as HTL materials. These HTL materials were observed to be optimized when dibenzothiophene and indole units were introduced as a core and substituents, respectively.…”