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Semi‐transparent organic solar cells (STOSCs) have great potential in power‐generating windows for building facades and automobiles. At present, the evaporated metal thin film is widely used as the transparent top electrode in STOSCs owing to its relatively high conductivity. However, its transmittance in the visible range is sacrificed for fulfilling the thickness requirement of the electrical percolation threshold. Herein, a facile approach of introducing pre‐located Ag nanoparticles (NPs) with an optimized amount of ligands is demonstrated to promote the high‐quality and ultrathin evaporated Ag film formation for high‐performance transparent electrodes beyond that of merely evaporated electrodes. With the pre‐located and ligand‐optimized Ag NPs, the growth of evaporated Ag clusters can be guided to form high‐quality transparent electrode. Equally important, the approach also reduces the mis‐stacking defects of the electron transport layer and thus favors the carrier transportation/extraction to the electrode. By using these Ag NPs/7 nm Ag with a sheet resistance less than 15 Ω sq−1 and average transmittance of 59.30% in the visible region as the main structure in the top electrode, a PM6:L8‐BO based STOSC achieves light utilization efficiency of 4.422% with a remarkable power conversion efficiency of 12.80%. This work provides a facile strategy to not only realize high‐quality and transparent ultrathin electrode with detailed understanding, but also to promote the practical applications of semi‐transparent photonic devices. [ABSTRACT FROM AUTHOR]

The inorganic hole transport layer of nickel oxide (NiOx) has shown highly efficient, low‐cost, and scalable in perovskite photovoltaics. However, redox reactions at the interface between NiOx and perovskites limit their commercialization. In this study, ABABr (4‐(2‐Aminoethyl) benzoic acid bromide) between the NiOx and different perovskite layers to address the issues has been introduced. How the ABABr interacts with NiOx and perovskites is experimentally and theoretically investigated. These results show that the ABABr molecule chemically reacts with the NiOx via electrostatic attraction on one side, whereas on the other side, it forms a strong hydrogen bond via the NH3+ group with perovskites layers, thus directly diminishing the redox reaction between the NiOx and perovskites layers and passivating the layer surfaces. Additionally, the ABABr interface modification leads to significant improvements in perovskite film morphology, crystallization, and band alignment. The perovskites solar cells (PSCs) based on an ABABr interface modification show power conversion efficiency (PCE) improvement by over 13% and maintain over 90% of its PCE after continuous operation at maximum power point for over 500 h. The work not only contributes to the development of novel interlayers for stable PSCs but also to the understanding of how to prevent interface redox reactions. [ABSTRACT FROM AUTHOR]

While there is promising achievement in terms of the power conversion efficiency (PCE) of perovskite solar cells (PSCs), long‐term stability has been considered the main obstacle for their practical application. In this work, the authors demonstrate the small monomer 2‐(dimethylamino) ethyl methacrylate (DMAEMA) with unsaturated carboxylic acid ester bond in the antisolvent for perovskite formation to improve the PCE and stability. The results show that DMAEMA is self‐polymerized and uniformly distributed in the film, contributing to the improved crystallinity of the perovskites. Equally important, it is found that there are newly established interactions of Pb2+ and DMAEMA, and iodine and ternary amine between DMAEMA and perovskites, which improves the uniformity of the lead (II) iodide vertical distribution along with the films and thus phase stability, as well as largely decreases defects density in the film. Overall, the inverted PSCs with DMAEMA exhibit a open‐circuit voltage of 1.10 V, short‐circuit current of 23.86 mA cm−2, fill factor of 0.82, and finally PCE reaches 21.52%. Meanwhile, the PSC stability is significantly improved due to the inhibition of the formation of iodine, reduction of the uncoordinated Pb2+, and suppression of phase segregation. [ABSTRACT FROM AUTHOR]

Abstract Two oxindole based π-conjugated polymers with same structures except the positions of selenium atoms in the main chains have been synthesized. The effects of heavy atom substitution on optical, electrochemical, and photovoltaic properties have been investigated. The polymer solar cell devices based on the new polymers as electron donors also have been studied. The oxindole based polymers showed intramolecular non-bonded interactions between divalent sulfur/selenium and carbonyl oxygen. The selenophene based polymers showed narrow optical band gaps. However, the introduction of selenophene led to the decline of optical absorption in both the monomer and the polymers compared with the thiophene based counterparts. The diminution of absorption in selenium containing polymers can have adverse effect on solar photon harvesting. Graphical abstract Image 1 Highlights • The effect of Se replacement on the optoelectronic properties of the polymers. • Introduction of Se atoms led to the decline of optical absorption in the polymers. • Intramolecular non-bonded interactions between divalent S/Se and carbonyl oxygen. [ABSTRACT FROM AUTHOR]

A new electron withdrawing monomer, cyano substituted (Z) -(thienylmethylene)-2-indolone (TEI(CN)) has been synthesized and polymerized with different donors to give three alternating donor/acceptor conjugated polymers. The cyano substituted polymers showed significantly reduced LUMO energy levels and small optical bandgaps compared with un-substituted polymer. The optical absorptions of new polymers mainly appeared in NIR range, peaked at 700–800 nm. With strong electron donor EDOT, the polymer, PTEI(CN)-EDOT showed most of its absorption in NIR region (>700 nm). The inverted bulk hetero-junction polymer solar cells based on two of the new polymers were fabricated and tested. [ABSTRACT FROM AUTHOR]

Lead sulphide (PbS) nanocrystals (NCs) are promising materials for low-cost, high-performance optoelectronic devices. So far, PbS NCs have to be first synthesized with long-alkyl chain organic surface ligands and then be ligand-exchanged with shorter ligands (two-steps) to enable charge transport. However, the initial synthesis of insulated PbS NCs show no necessity and the ligand-exchange process is tedious and extravagant. Herein, we have developed a direct one-step, scalable synthetic method for iodide capped PbS (PbS-I) NC inks. The estimated cost for PbS-I NC inks is decreased to less than 6 $·g−1, compared with 16 $·g−1 for conventional methods. Furthermore, based on these PbS-I NCs, photodetector devices show a high detectivity of 1.4 × 1011Jones and solar cells show an air-stable power conversion efficiency (PCE) up to 10%. This scalable and low-cost direct preparation of high-quality PbS-I NC inks may pave a path for the future commercialization of NC based optoelectronics. Providing large-scale iodide capped semi-conductive PbS nanocrystals inks preparation for high-throughput manufacturing remains a challenge. Here, the authors propose a direct one step and scalable synthesis method enabling cost reduction and promoting its commercial viability for solar cells. [ABSTRACT FROM AUTHOR]