Deep Absorbing Porphyrin Small Molecule for High-Performance Organic Solar Cells with Very Low Energy Losses

Abstract

We designed and synthesized the DPPEZnP-TEH molecule, with a porphyrin ring linked to two diketopyrrolopyrrole units by ethynylene bridges. The resulting material exhibits a very low energy band gap of 1.37 eV and a broad light absorption to 907 nm. An open-circuit voltage of 0.78 V was obtained in bulk heterojunction (BHJ) organic solar cells, showing a low energy loss of only 0.59 eV, which is the first report that small molecule solar cells show energy losses <0.6 eV. The optimized solar cells show remarkable external quantum efficiency, short circuit current, and power conversion efficiency up to 65%, 16.76 mA/cm(2), and 8.08%, respectively, which are the best values for BHJ solar cells with very low energy losses. Additionally, the morphology of DPPEZnP-TEH neat and blend films with PC61BM was studied thoroughly by grazing incidence X-ray diffraction, resonant soft X-ray scattering, and transmission electron microscopy under different fabrication conditions.

High‐Performance Polymer Tandem Solar Cells Employing a New n‐Type Conjugated Polymer as an Interconnecting Layer

“…A 2 nm Ag fi lm was deposited to further improve the recombination property at the ETL/HTL interface. A wide bandgap PThBDTP:PC 71 BM [ 39 ] sub-cell (sub-cell 1) and a narrow bandgap DPPEZnP-TEH:PC 61 BM [ 40 ] sub-cell (sub-cell 2) were chosen to construct the tandem OSC as they show complementary absorption and also both of them can produce single-junction cells with high effi ciency. The tandem OSC structure is ITO/PEDOT:PSS/sub-cell 1/PF3N-2TNDI/ Ag(2 nm)/PEDOT:PSS/sub-cell 2/PF3N-2TNDI/Ag.…”

“…For the front cell, a PCE of 8.86% with J sc of 12.6 mA cm −2 , V oc of 0.95 V, and fi ll factor (FF) of 74% was achieved, while for the back cell, a PCE of 8.09% with J sc of 17.01 mA cm −2 , V oc of 0.78 V, and FF of 61% was achieved based on the fabrication procedure in previous report. [ 40 ] Despite the fact that both cells show high PCEs, the FF obtained in the back cell is obviously lower, which may lead to poor tandem cell effi ciency. [ 41 ] Therefore, we further optimized the back-cell performance by employing solvent vapor annealing (SVA) treatment, which is a simple and effective way for improving the absorption, morphology, and charge mobility in small molecule-based BHJ.…”

π-Linkage effect of push-pull-structure organic small molecules for photovoltaic application

“…The most successful push-pull-structure donor materials employing ethynylbenzene as π-bridges were obtained by Peng et al [89]. They designed the molecule named 32 with a porphyrin ring linked to two DPP units by ethynylene bridges.…”

Hybrid Photoconductive Cathode Interlayer Materials Composed of Perylene Bisimide Photosensitizers and Zinc Oxide for High Performance Polymer Solar Cells

“…[20] PTB7 served again as the host polymer, PC 71 BM served as the electron accepting material, and a recently developed porphyrindiketopyrrole molecule (DPPEZnP-TEH) contributed the near-IR sensitization. [21] The composite film of PTB7:DPPEZnP-THE:P71BM showed absorption beyond 900 nm, marking a breakthrough in ternary OSC research. To realize the full potential of this novel ternary system, the photoconductive cathode interlayer (ZnO:PBI-H) was used to reduce the recombination at the interface between active layer and electrode.…”