Initial Engineering and Outdoor Stability Assessment of “Gray/Black” Fullerene-Free Organic Photovoltaics Based on Only Two Complementary Absorbing Materials: A Tetrabenzotriazacorrole and a Subphthalocyanine

Abstract

Broad absorption is a desired characteristic of materials employed in the photoactive layers of organic photovoltaic (OPV) devices. Here, we have identified tetrabenzotriazacorroles (Tbcs) as complementary absorbing chromophores and electron donors to the promising nonfullerene acceptors boron subphthalocyanines (BsubPcs). These two materials, which can be utilized as donor–acceptor pairs within fullerene-free OPVs, yield spectral coverage over the entire visible range of 300–750 nm. Oxy phosphorus Tbc derivative (POTbc) was employed as an electron donor and paired initially with multiple BsubPc derivatives having a distribution of highest occupied molecular orbital/lowest unoccupied molecular orbital energy levels in planar heterojunction OPVs. These devices were “gray/black” due to the broad absorption across the visible spectrum. Upon screening, the partially halogenated chloro hexachloro BsubPc (Cl–Cl 6 BsubPc) showed the greatest promise for coupling with POTbc. The thickness ratio and total thickness of the active layer were then probed in order to identify the optical and electrical limitations on the POTbc/Cl–Cl 6 BsubPc-based OPV device. A maximum power conversion efficiency (PCE) of 2.13% was achieved at 60 nm total thickness of the active layer and 1 to 3 (POTbc to Cl–Cl 6 BsubPc) thickness ratio. Outdoor stability of the champion device was evaluated using protocols established by International Summits on OPV Stability and was found to be on par with an α-sexithiophene/Cl–Cl 6 BsubPc baseline OPV.

β‐Isoindigo‐azaDIPYs: Fully Conjugated Hybrid Systems with Broad Absorption in the Visible Region

“…Beyond their traditional utilization as dyes and pigments, indigo‐based chromophores have been extensively studied over the past decade as non‐fullerene acceptors in organic solar cells (OSCs) and active components of field‐effect transistors (FETs) [1–7] . In comparison, the chemistry of the structural isomer β‐isoindigo remains largely unexplored, despite the presence of this structural unit (in the cis ‐configuration) in well‐known π‐extended chromophores such as tetrabenzotriazocorroles [8–15] and expanded phthalocyanines [16] . The dearth of attention paid to β‐isoindigo‐based chromophores can be attributed to their inconvenient syntheses [16–25] .…”

Dual-Band, Efficient Self-Powered Organic Photodetectors with Isotype Subphthalocyanine-Based Heterojunctions toward Secure Optical Communications

“…Traditionally, most of the reported SubPcs used in OPDs are p-type materials with peripheral substitution, while axial substitution also plays an important role in manipulating the molecular energy level and charge carrier transfer . Until now, the axial substituents of BSubPcs are dominated by halogens. , However, the boron–halogen (B–Cl or B–Br) bond is sensitive to the air environment, producing either B–OH or the dehydrated “B–O–B” dimeric species, which affects the longevity of an electronic device. In fact, nonhalogen substituents are equally capable of adjusting the optoelectronic characteristics of SubPcs. , To our knowledge, SubPc derivatives as electron acceptors have been rarely reported in the field of OPDs.…”

“…27 Until now, the axial substituents of BSubPcs are dominated by halogens. 22,28 However, the boron−halogen (B−Cl or B−Br) bond is sensitive to the air environment, producing either B− OH or the dehydrated "B−O−B" dimeric species, which affects the longevity of an electronic device. In fact, nonhalogen substituents are equally capable of adjusting the optoelectronic characteristics of SubPcs.…”

Novel phosphorus(v) tetrabenzotriazacorroles: synthesis, characterization, optical, electrochemical, and femtosecond nonlinear optical studies

“…Despite the straightforward synthesis of TBCs and their interesting optical and electrochemical properties, they have been seldom explored for optoelectronic applications. 26–29…”

“…Despite the straightforward synthesis of TBCs and their interesting optical and electrochemical properties, they have been seldom explored for optoelectronic applications. [26][27][28][29] TBCs are potential NLO molecules with superior absorption properties compared to Pcs. Further, Pcs possess good thirdorder NLO properties compared to their second-order NLO properties because they possess a center of symmetry, and consequently the absence of a permanent dipole moment, which is important to demonstrate good second-order hyperpolarizability.…”