Passivating surface and bulk defects of perovskite films has been proven to be an effective way to minimize nonradiative recombination losses in perovskite solar cells (PVSCs). The lattice interference and perturbation of atomic periodicity at the perovskite surfaces often significantly affect the material properties and device efficiencies. By tailoring the terminal groups on the perovskite surface and modifying the surface chemical environment, the defects can be reduced to enhance the photovoltaic performance and stability of derived PVSCs. Here, we report a rationally designed bifunctional molecule, piperazinium iodide (PI), containing both R 2 NH and R 2 NH 2 + groups on the same six-membered ring, behaving both as an electron donor and an electron acceptor to react with different surface-terminating ends on perovskite films. The resulting perovskite films after defect passivation show released surface residual stress, suppressed nonradiative recombination loss, and more n-type characteristics for sufficient energy transfer. Consequently, charge recombination is significantly suppressed to result in a high open-circuit voltage (V OC ) of 1.17 V and a reduced V OC loss of 0.33 V. A very high power conversion efficiency (PCE) of 23.37% (with 22.75% certified) could be achieved, which is the highest value reported for inverted PVSCs. Our work reveals a very effective way of using rationally designed bifunctional molecules to simultaneously enhance the device performance and stability.

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the demands for energy storage and conversion systems of high energy and power density increase rapidly. To meet the everincreasing demands, transition metal compounds have been widely studied as catalysts for chemical and energy transformation processes (e.g., oxygen reduction and evolution reaction) [1][2][3][4] and as electrode materials for rechargeable batteries [5][6][7] and supercapacitors. [8][9][10][11][12][13] For example, nickel hydroxides (Ni(OH) 2 ) have been successfully used in rechargeable alkaline batteries (due to their low-cost and high capacity) [5,14] and in hybrid supercapacitors (due to high rate capability). [15] Hybrid supercapacitors, composed of a capacitive electrode and a battery-type Faradaic electrode, have demonstrated significantly higher energy density than conventional carbon-based electrical double-layer capacitors (EDLCs), due largely to the higher capacity of the battery-type electrode and the broader voltage window of the electrode pair. [16][17][18][19][20] Moreover, hybrid supercapacitors can achieve much higher power density than rechargeable batteries. Typically, one electrode of a hybrid supercapacitor is a carbon-based material whereas the other electrode (i.e., battery-type electrode) is a lithium electroactive material (such as Sn [16] and Li 4 Ti 5 O 12 [21] ) or an anionic redox active transition metal-based oxide/hydroxide. [15,22] As a promising battery-type electrode for hybrid supercapacitor in alkaline electrolyte, Ni(OH) 2 usually exhibits a pair of distinctly separated Faradaic redox peaks due to its phase transition. [23] This material was widely reported as a "pseudocapacitive" material for supercapacitors in the past decade, [24][25][26][27][28][29][30] but has recently been regarded as a battery-type material because of its batterytype behavior in alkaline media. [31][32][33] However, Ni(OH) 2 electrodes usually suffer from an irreversible phase transition, [34,35] large volume variation, [14] and low electronic conductivity, [36] resulting in poor durability and limited rate capability.Numerous efforts have been devoted to addressing the above issues. In order to enhance the electronic conductivity, an electronically conductive second phase has been introduced [15,24,37] or Ni(OH) 2 has been grown on a conductive substrate. [28,38,39] As a highly conductive two-demonstrational material with high surface area, graphene is an ideal substrate to improve the electronic conductivity of Ni(OH) 2 . [15,24,40] To further improve Compact, light, and powerful energy storage devices are urgently needed for many emerging applications; however, the development of advanced power sources relies heavily on advances in materials innovation. Here, the findings in rational design, one-pot synthesis, and characterization of a series of Ni hydroxide-based electrode materials in alkaline media for fast energy storage are reported. Under the guidance of density functional theory calculations and experimental investigations, a composite electrode composed of Co-/Mn-substituted...

Lead halide perovskite and organic solar cells (PSCs and OSCs) are considered as the prime candidates currently for clean energy applications due to their solution and low‐temperature processibility. Nevertheless, the substantial photon loss in near‐infrared (NIR) region and relatively large photovoltage deficit need to be improved to enable their uses in high‐performance solar cells. To mitigate these disadvantages, low‐bandgap organic bulk‐heterojunction (BHJ) layer into inverted PSCs to construct facile hybrid solar cells (HSCs) is integrated. By optimizing the BHJ components, an excellent power conversion efficiency (PCE) of 23.80%, with a decent open‐circuit voltage (Voc) of 1.146 V and extended photoresponse over 950 nm for rigid HSCs is achieved. The resultant devices also exhibit superior long‐term (over 1000 h) ambient‐ and photostability compared to those from single‐component PSCs and OSCs. More importantly, a champion PCE of 21.73% and excellent mechanical durability can also be achieved in flexible HSCs, which is the highest efficiency reported for flexible solar cells to date. Taking advantage of these impressive device performances, flexible HSCs into a power source for wearable sensors to demonstrate real‐time temperature monitoring are successfully integrated.