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Two dimensional Dion-Jacobson (2D DJ) perovskite has emerged as a potential photovoltaic material because of its unique optoelectronic characteristics. However, due to its low structural flexibility and high formation energy, extra assistance is needed during crystallization. Herein, we study the solvent effect on film formation and trap states of 2D DJ perovskite. It is found that the nucleation process of 2D DJ perovskite can be retarded by extra coordination, which is proved by in situ optical spectra. As a benefit, out-of-plane oriented crystallization and ordered phase distribution are realized. Finally, in 1,5-pentanediammonium (PeDA) based 2D DJ perovskite solar cells (PSCs), one of the highest reported open-circuit voltage (

The stability of organic solar cells is a key issue to promote practical applications. Herein, we demonstrate that the device performance of organic solar cells is enhanced by an Ir/IrOx electron-transporting layer, benefiting from its suitable work function and heterogeneous distribution of surface energy in nanoscale. Notably, the champion Ir/IrOx-based devices exhibit superior stabilities under shelf storing (T80 = 56696 h), thermal aging (T70 = 13920 h), and maximum power point tracking (T80 = 1058 h), compared to the ZnO-based devices. It can be attributed to the stable morphology of photoactive layer resulting from the optimized molecular distribution of the donor and acceptor and the absence of photocatalysis in the Ir/IrOx-based devices, which helps to maintain the improved charge extraction and inhibited charge recombination in the aged devices. This work provides a reliable and efficient electron-transporting material toward stable organic solar cells.

Although the photovoltaic performance of perovskite solar cells (PSCs) has reached the commercial standards, the unsatisfactory stability limits their further application. Hydrophobic interface and encapsulation can block the damage of water and oxygen, while the instability induced by intrinsic residual strain remains inevitable. Here, the residual strain in a two-dimensional (2D) Ruddlesden-Popper (RP) perovskite film is investigated by X-ray diffraction and atomic force microscopy. It's found that the spacer cations contribute to the residual strain even though they are not in the inorganic cages. Benefited from strain relaxation, the film quality is improved, leading to suppressed recombination, promoted charge transport and enhanced efficiency. More significantly, the strain-released devices maintain 86 % of the initial efficiency after being kept in air with 85 % relative humidity (RH) for 1080 h, 82 % under maximum power point (MPP) tracking at 50 °C for 804 h and 86 % after continuous heating at 85 °C for 1080 h.

Experimental determination of equilibrium solubility of 1-(2-bromophenyl)-pyrrole-2,5-dione in binary aqueous solutions containing a co-solvent of isopropanol, ethanol, N-methyl-2-pyrrolidinone (NM...

In comparison to widely adopted bulk heterojunction (BHJ) structures for organic solar cells (OSC), exploiting the sequential deposition to form planar heterojunction (PHJ) structures enables to realize the favorable vertical phase separation to facilitate charge extraction and reduce charge recombination in OSCs. However, effective tunings on the power conversion efficiency (PCE) in PHJ-OSCs are still restrained by the currently available methods. Based on a polymeric donor PBDBT-2F (PBDBT= Poly [[4,8-bis [5-(2-ethylhexyl)-4-fluoro-2-thienyl]benzo [1,2- b :4,5- b ′]dithiophene-2,6-diyl]-2,5-thiophenediyl [5,7-bis (2-ethylhexyl)-4,8-dioxo-4 H ,8 H -benzo [1,2- c :4,5- c ′]dithiophene-1,3-diyl]-2,5-thiophenediyl]) and a non-fullerene (NF) acceptor Y6, we proposed a strategy to improve the properties of photovoltaic performances in PHJ-based OSCs through dilute dispersions of the PBDBT-2F donor into the acceptor-dominant phase with the sequential film deposition. With the control of donor dispersions, the charge transport balance in the PHJ-OSCs is improved, leading to the expedited photocarrier sweep-out with reduced bimolecular charge recombination. As a result, a PCE of 15.4% is achieved in the PHJ-OSCs. Importantly, the PHJ solar cells with donor dispersions exhibit better thermal stability than corresponding BHJ devices, which is related to the better film morphology robustness and less affected charge sweep-out during the thermal aging.

Herein, a new electropolymerized (EP) film named poly-triphenylcarbazole fluoranthene (p-TPCF) has been in situ synthesized by an electrochemical cyclic voltammetry method and applied to tune the work-function (WF) of the PEDOT:PSS hole-transporting layer (HTL) in organic solar cells (OSCs). Multiple techniques, including Kelvin probe force microscopy (KPFM), light intensity dependent solar cell characterization, Mott–Schottky analysis, and transient photovoltage (TPV) and transient photocurrent (TPC) measurements, have been explored to provide insights into the mechanism. Benefiting from the deeper work-function (WF), larger built-in voltage (Vbi), decreased recombination, and longer carrier lifetime, the devices with EP films exhibited superior device performance with simultaneously enhanced Voc, Jsc and FF.

The solubilities of 1-(2-bromo-phenyl)-pyrrole-2,5-dione in 14 pure solvents including isopropanol, methanol, isobutanol, ethanol, n-propanol, n-butanol, ethylene glycol (EG), cyclohexane, acetone,...

The cathode interlayer plays a key role in the photovoltaic performance in organic solar cells. In this work, we demonstrate that polydopamine/ZnO can be used as efficient electron transport layers (ETL) in inverted non-fullerene organic solar cells. In comparison to the devices with the ZnO ETL, the power conversion efficiency of inverted PBDBT:ITIC solar cells with the PDA/ZnO ETL can be boosted from 10.15% to 11.14%, due to the simultaneously enhanced open-circuit voltage, short-circuit current and fill factor. The increased photovoltaic performance is mainly attributed to a faster charge extraction ability at the cathode interface and longer carrier lifetime, confirmed by transient optoelectrical analyses. Revealed by conductive-AFM and KPFM coupled with absorption spectroscopy, high optical transmittance and vertical electrical conductivity with a suitable low work function and a doping effect induced by PDA were observed in the PDA modified ZnO, which makes it a good ETL material for inverted solar cells and indicated universal applicability. This work provides a new approach to modify the cathode interfacial properties towards high efficiency organic solar cells with non-fullerene acceptors.

N-[(4-Bromo-3,5-difluorine)phenyl]maleimide (BDPM) is a new monomer for polyreaction. Its corresponding solid−liquid equilibrium data provide essential support for industrial design and further the...

The solubility of N-[(4-bromo-3,5-difluorine)-phenyl]maleimide in pure pyridine, acetone, tetrahydrofuran, ethanol, trichloromethane, and acetonitrile at temperature between (285.00 and 350.15) K under atmospheric pressure was investigated. A laser monitoring observation technique was used to determine the dissolution of the solid phase in solid + liquid mixture. The experimental solubility data were correlated with the modified Apelblat equation.

The solubility of N-[(4-bromo-3,5-difluorine)phenyl]acrylamide (BDPA) in pure benzene, methanol, pyridine, ethanol, acetonitrile, and toluene was measured at temperatures ranging from (284.65 to 34...