Anode interlayer in organic photovoltaics: Narrow bandgap small molecular materials as exciton‐blocking layer

Abstract

Six materials were used as an interlayer at the anode side (anode interlayer [AIL]) of an archetypical planar heterojunction organic solar cell (OSC). In addition to two conventional wide bandgap hole transport materials (HTMs), tris(4‐carbazol‐9‐ylphenyl)amine (TCTA) and trans‐4,4′‐bis[N‐(naphthalen‐1‐yl)‐N‐phenylamino]stilbene (NPAE), we explore four narrow bandgap materials, bis(biphenylaminospiro)‐fumaronitrile (PhSPFN), bis(N‐(naphthalen‐1‐yl)‐N‐phenylamino)anthraquinone (NPAAnQ), bis‐(di(2‐fluorophenyl)aminospiro)‐fumaronitrile (FPhSPFN), and bis[4‐(N‐(pyren‐1‐yl)‐N‐phenylamino)phenyl]fumaronitrile (PyPAFN), the energy levels of which essentially align with the ones of SubPc, the active light‐absorbing material of the OSC study herein. By using a narrow bandgap AIL, universally enhanced short‐circuit current density and power conversion efficiencies (PCEs) have been achieved. In addition, one of these materials, FPhSPFN, results in a PCE of 5.13%, which is the highest reported value for SubPc solar cells with a similar architecture. This is ascribed to the formation of an otherwise passive exciton‐blocking interface. Furthermore, this demonstrates that charge selectivity by way of a high‐lying lowest unoccupied molecular orbital (LUMO) energy level is not a prerequisite for successful AIL design. As such, in terms of energy level alignment and bandgap energies, we establish a viable alternative approach toward interface and interlayer material design.

Recent advances in subphthalocyanines and related subporphyrinoids

“…345,346 In the case of SubPcs, rather than employing pristine BCP, the dilution of BCP with C 60 has been found to further improve the device performance and lifetime. 347 Several other exciton blockings, such as N,N-dicarbazolyl-3,5-benzene, 348 buffer layer of bis-(naphthylphenylaminophenyl)fumaronitrile 349 or bis-(di(2fluorophenyl)aminospiro)-fumaronitrile, 350 have also proven to be effective by showing remarkable PCEs as high as 5.08, 4.77 or 5.13%, respectively. To a lesser extent, the substitution of the EBM by electron transport materials (ETM) has also been investigated.…”

Enhanced photovoltaic performance of dye‐sensitized solar cell based on ZnO nanoparticles and ZnO/graphene nanocomposites

“…[8,9] Till now, most studies have been focused on the investigation of efficiency and cost of solar cell. [10][11][12][13][14] In recent decades in which nanoscience and nanotechnology have emerged, various nanostructures have been synthesized and applied in dye-sensitized solar cell (DSSC) devices. Carbon-based nanostructures, an interesting group of nanomaterials that have unique properties such as chemical and thermal stability, availability, low-cost production, high surface area, and biocompatibility have been attracted more attention in DSSC-related researches.…”