a) E gap was determined from the intersection of the EQE edge and the local EQE maximum; b) V oc was calculated from the measured J-V curves; c) V oc rad was calculated from FTPS and EL measurements; d) EQE EL is the EL quantum efficiency of the fabricated devices; e) Exp. ΔE 3 is calculated with the Equation (ΔE 3 = −kTln(EQE EL )).

Manipulating the donor:acceptor (D:A) energetics, e.g. the highest occupied molecular orbital (HOMO) offset, is the key to balancing the charge separation and charge recombination for high-performance organic solar cells (OSCs)....

performance, superior flexibility, vivid colors, unique transparency, potential lowcost production with solution processing, etc. [1][2][3][4][5][6][7][8][9] The recent years have witnessed a great leap in device performance and device stability, which are attributed to the delicate molecular structure design, advanced morphology manipulation technology, and device structure evolution. [10][11][12][13][14][15][16][17][18][19] Currently, the best-performed OPVs exhibit a certified efficiency of 19.3% for single junction device and 20.0% for tandem structure, as well as an extrapolated device stability with T 80 over 30 years. [20][21][22] While compared to their inorganic counterparts (e.g., for siliconbased PVs, the efficiency is over 26%), the OPVs are still inferior in efficiency. [23] Therefore, it would be urgent to further improve the device efficiency of OPV, which will require an in-depth understanding on the working principles of OPV, as well as the development of effective strategies to balance the charge generation, transport, and recombination. Among all the strategies, it is generally observed that adding a third component to construct the ternary blend is a very simple but effective method to further boost the device performance of OPVs. [24][25][26][27][28][29][30][31][32] A bunch of benefits have been demonstrated with the multicomponentThe ternary blend is demonstrated as an effective strategy to promote the device performance of organic photovoltaics (OPVs) due to the dilution effect. While the compromise between the charge generation and recombination remains a challenge. Here, a mixed diluent strategy for further improving the device efficiency of OPV is proposed. Specifically, the high-performance OPV system with a polymer donor, i.e., PM6, and a nonfullerene acceptor (NFA), i.e., BTP-eC9, is diluted by the mixed diluents, which involve a high bandgap NFA of BTP-S17 and a low bandgap NFA of BTP-S16 (similar with that of the BTP-eC9). The BTP-S17 of better miscibility with BTP-eC9 can dramatically enhance the open-circuit voltage (V OC ), while the BTP-S16 maximizes the charge generation or the short-circuit current density (J SC ). The interplay of BTP-17 and BTP-S16 enables better compromise between charge generation and recombination, thus leading to a high device performance of 19.76% (certified 19.41%), which is the best among single-junction OPVs. Further analysis on carrier dynamics validates the efficacy of mixed diluents for balancing charge generation and recombination, which can be further attributed to the more diverse energetic landscapes and improved morphology. Therefore, this work provides an effective strategy for highperformance OPV for further commercialization.

Side chain modification upon small-molecule acceptors (SMAs) is an effective method to realize high device efficiencies for organic solar cells (OSCs), among which the asymmetric side-chain strategy is a promising...

Prefabricated construction has been proven effective, environmentally-friendly, and labor-friendly. It is widely considered a sustainable approach to the construction industry. China is still in the initial process of adopting prefabricated construction practices and has conducted a few studies to date on the constraints of prefabricated construction up to the operation stage. This paper focuses on the major factors obstructing prefabricated construction development in China. Twenty-three variables affecting said development are summarized per the results of a literature review and a semi-structured interview. A questionnaire was delivered to developers, designers, contractors, engineers, component suppliers, and property managers. A total of 160 valid respondents were collected. Twenty-three variables were ranked by the mean score after an Analysis of Variance (ANOVA) indicated that no statistical differences in the data from six stakeholders. Principal Component Analysis (PCA) was employed to reduce the dimensionality of four factors: industry chain, cost, social climate and public opinion, and risk. The risk is found to be the main influencing factor even though it is rarely the focal point of research on prefabricated construction. The findings presented in this paper may assist different stakeholders in better understanding issues with prefabricated construction practices in China at present and, therefore, find workable solutions.