Design and engineering of highly efficient light-harvesting nanomaterial systems to emulate natural photosynthesis for maximizing energy conversion have stimulated extensive efforts. Here we present a new class of photoactive semiconductor nanocrystals that exhibit high-efficiency energy transfer for enhanced photocatalytic hydrogen production under visible light. These nanocrystals are formed through noncovalent self-assembly of In­(III) meso-tetraphenylporphine chloride (InTPP) during microemulsion assisted nucleation and growth process. Through kinetic control, a series of uniform nanorods with controlled aspect ratio and high crystallinity have been fabricated. Self-assembly of InTPP porphyrins results in extensive optical coupling and broader coverage of the visible spectrum for efficient light harvesting. As a result, these nanocrystals display excellent photocatalytic hydrogen production and photostability under the visible light in comparison with the commercial InTPP porphyrin powders.

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Fused aromatic cores in non-fullerene electron acceptors (NFEAs) play a significant role in determining their optoelectronic properties and photovoltaic performance. In this work, a dodecacyclic-fused core with three electron-deficient units is synthesized through a double intramolecular Cadogan reduction cyclization. Terminal groups with different halogen substitution (F or Cl) are grafted onto the dodecacyclic-fused core to afford MS-4F and MS-4Cl, both of which showed strong and broad absorption, narrow bandgaps around 1.40 eV, and variable molecular packing model in pristine and blend films.Photovoltaic performance of solar cells containing MS-4F and MS-4Cl as NFEAs were investigated with resultant power conversion efficiencies (PCEs) of 11.75 % and 11.79 %, respectively. The mechanism study indicates that both of PBDB-T : MS-4F-and PBDB-T : MS-4Cl-based devices displayed high hole and electron mobility values, efficient charge transfer, and low charge recombination etc. These results indicate that designing multiple-fused aromatic cores with multiple electron-deficient units is a promising strategy to obtain high-performance NFEAs.

Advances of small-molecular acceptors (SMAs) recently have motivated the development of high-performance organic solar cells (OSCs). The SMAs featuring A–D–C–D–A framework have attracted numerous attention due to their facile tunability on chemical structures and in commercial synthesis. In this work, dithienobenzothiadiazol (DTBT) was utilized as the center (C) unit of A–D–C–D–A SMAs and three corresponding SMAs named DTBCIC-Cl, DTBCIC-F, and DTBCIC-H were synthesized by altering the terminal groups. The variation of terminal groups endowed SMAs with different performances, including optical absorbance, energy levels, and molecular packing, etc. In comparison to DTBCIC-H, DTBCIC-Cl and DTBCIC-F obtained by halogenation showed red-shift absorption, well matched energy levels with the polymer donor PM6, as well as closer molecular packing, rendering the blend films based on PM6:DTBCIC-Cl and PM6:DTBCIC-F wide absorption and improved morphology. High power conversion efficiency of 12.71% was thus obtained for OSCs based on DTBCIC-Cl. The results prove that optimization of SMAs via altering terminal groups provides a promising design strategy to obtain high-performance A–D–C–D–A SMAs.

In organic solar cells, interfacial materials play essential roles in charge extraction, transportation, and collection. Currently, highly efficient and thickness-insensitive interfacial materials are urgently needed in printable large area module devices. Herein, water/alcohol-soluble conjugated polyelectrolyte PFNBT-Br, with medium bandgap based on benzothiadiazole, are doped by two alkali metal sodium salts, NaH 2 PO 2 , Na 2 C 2 O 4 with different counter anions, to pursue high efficiency and thickness-insensitive electron-transport layers. Results show that the doping of electron-transport material can effectively promote the performance of the devices. Moreover, electron-transport layers doped by these salts with different counter anions show different behaviors in performances. Among which, the salt with oxalate anion C 2 O 4 2− (also named Ox 2− ) shows much better device performance than the salt with hypophosphite anion (H 2 PO 2 − ), especially under the thick film condition (e.g., 50 nm). The greatly enhanced performances of interfacial material doped by Ox 2− are due to reduced series resistance between the active layer material and the electrode, reduced dark-current, improved charge transport, and extraction efficiency, and decreased charge recombination for the devices at thick-film condition. These results demonstrated that n-doping could be a great potential strategy for making thickness-insensitive interfacial layers, besides, the performances can be further improved by carefully selecting salts.