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A strategy of incorporating transparent inorganic semiconductors is proposed for high-performance semitransparent organic photovoltaics. Visible-transparent p-type inorganic semiconductor copper(I) thiocyanate (CuSCN) and a near-infrared acceptor BTP-eC9 can form a heterojunction with exciton dissociation ability.

Solid additive engineering has been intensively explored on morphology tuning for highly efficient all-polymer solar cells (all-PSCs), a promising photovoltaic technology towards multi-scenario application. Although the nano-fibrillar network of the active layer induced by additive treatment is confirmed as the key factor for power conversion efficiency (PCE) of all-PSCs, its formation mechanism is not clearly revealed, for lack of precise and convincing real-time observation of crystallization and phase separation during the liquid-to-solid transition process of spin-coating. Herein we report an in-situgrazing incidence wide-angle/small-angle X-ray scattering (GIWAXS/GISAXS) screening that reveals the fact that naphthalene derived solid additives can suppress the aggregation of the polymer acceptor (PY-IT) at the beginning stage of spin coating, which provides sufficient time and space for the polymer donor (PM6) to form the fibril structure. Moreover, guided by this knowledge, a ternary all-polymer system is proposed, which achieves cutting-edge level PCEs for both small-area (0.04 cm2) (also decent operational stability) and large-area (1 cm2) devices.For the first time in-situGIWAXS and GISAXS technology is applied to spin-coated all-polymer active layers, successfully revealing new mechanisms on solid additive's morphology regulation effect.

A novel fluoro-methoxylated end group for Y-series acceptors is produced, and asymmetric substitution strategy is applied as a step-by-step optimization.19.24% power conversion efficiency is achieved for industrially compatible solvent ortho-xylene processed organic solar cells.Underlying morphological and photo-physical variation is revealed for device performance difference brought by solvent selection, which could set up a template for future research on similar topics.

A profound comprehension of the intricate relationships among molecular structure, morphology defining treatment processes, and performance is pivotal for advancing the development of highly efficient organic solar cells (OSCs). In this study, we synthesized a series of donor molecules with varying conjugate skeleton lengths and end-groups, named 3BDTBDD, 5BDTBDD, DRCN3BDT, and DRCN5BDT. Compared to control donors, the oligomer DRCN5BDT exhibits a red-shifted and broader absorption spectrum, enhanced charge-carrier mobility, and optimal crystallinity, attributed to its elongated conjugate skeleton and electron-withdrawing end-group. Consequently, OSCs based on DRCN5BDT:Y6 achieve a remarkable power conversion efficiency (PCE) of 14.04 % in binary oligomer OSCs. Furthermore, DRCN5BDT demonstrated impressive compatibility in ternary OSCs, yielding PCEs of 18.93 % (PM6:DRCN5BDT:BTP-eC9) and 17.45 % (PM6:DRCN5BDT:PY-IT). More importantly, this series of materials provided a clear research framework that enabled us to elucidate the intricate relationship between the widely use yet mystery solvent vapor annealing (SVA) treatment conditions and donor-acceptor aggregation states, employing in situ absorption spectroscopy. Our study provides valuable insights into the intricate connection between molecular structure and properties, offering crucial guidance for the design of efficient donor materials and device optimization of OSCs.

All-polymer solar cells (APSCs) are one of the most promising types of application-oriented photovoltaic technologies because they are operationally and mechanically stable; however, their low power conversion efficiency (PCE) restricts the core competitiveness against other types of solar cells. Besides, poor insight of mechanical performance, such as ductility, has been revealed for cutting-edge APSCs. Herein, we chose two well miscible polymer donors, PM6 and J71, and achieved a PCE of 16.52% for APSCs in a ternary blend with PY-IT and 15.74% for air-processed devices. The improvement is enabled by effective energy transfer, tuned crystallinity, and improved phase separation, which resulted in faster charge transfer and more balanced charge transport, suppressed exciton recombination, and more efficient charge extraction. Furthermore, the good miscibility between two donors enabled the target to have well-maintained film morphology without damaging the initial nanoscale network, bringing comparable film ductility. Last, the inner structure-property relationship of photovoltaic and morphological parameters, and film ductility was illustrated by a correlation study.

There is an urgent demand for all-polymer organic solar cells (AP-OSCs) to gain higher efficiency. Here, we successfully improve the performance to 16.09% by introducing a small amount of BN-T, a B←N-type polymer acceptor, into the PM6:PY-IT blend. It has been found that BN-T makes the active layer, based on the PM6:PY-IT:BN-T ternary blend, more crystalline but meanwhile slightly reduces the phase separation, leading to enhancement of both exciton harvesting and charge transport. From a thermodynamic viewpoint, BN-T prefers to reside between PM6 and PY-IT, and the fraction of this fine-tunes the morphology. Besides, a significantly reduced nonradiative energy loss occurs in the ternary blend, along with the coexistence of energy and charge transfer between the two acceptors. The progressive performance facilitated by these improved properties demonstrates that AP-OSCs can possibly comparably efficient with those based on small molecule acceptors, further enhancing the competitiveness of this device type.

Commercial activated carbon (CAC) was modified using low-pressure radio frequency nitrogen plasma discharge (NPD) operating at 0.3 mbar and 40 kHz. The surface chemistry of CAC was modified using HNO3 pre-oxidation to possibly influence the reactivity of NPD. The results of x-ray photoelectron spectroscopy (XPS) suggested that pre-oxidation reduces aromaticity, generates aliphatic carbons (C-C and C-H), and increases carboxylic functional groups (COOH) which probably enhances the nitrogen plasma functionalization based on the N/C ratio for CAC-O-P (4.29 %) compared to CAC-P (2.88 %). FTIR was used to confirm such effects of pre-oxidation from the functional groups present on the carbon surface. The total surface area was identified using Langmuir and Brunauer–Emmett–Teller (BET) N2 adsorption isotherms at 77 K. Both pre-oxidation and plasma treatment caused an increase in the surface area of CAC up to 150 percent. Carbon t-plot method was used to determine the micropore volume, micropore area, and external surface area. The total surface area of each activated carbon was mostly constituted of micropore area which was identified to be directly proportional to the micropore volume. Scanning electron microscope (SEM) confirms the destruction of the surface morphology for CAC-O that might have caused the increase in surface area. Development of surface threadlike structures were observed for the NPD treated CAC-O. NPD favors the development of NH2 functionalities and reduces the aromaticity of activated carbons while enhancing the surface morphology and the surface area.