【Adv.Mater.】吉林大学王晓峰等|羟基界面工程赋能钙钛矿太阳能电池实现26.6%超高效率#

(a) Schematic diagram of the synthesis process of hydroxylated V2CTx MXene. (b) XRD patterns of V2AlC MAX, V2CTx MXene, and V2C-OH MXene. (c) Fourier transform infrared (FTIR) spectra, (d) X-ray photoelectron spectroscopy (XPS) survey spectra of V2CTx MXene and V2C-OH MXene (“*” represents the Na KLL Auger signal). High-resolution XPS spectra of (e) O 1s, f) C 1s, and (g) V 2p for the V2CTx MXene and V2C-OH MXene.#

在界面结构与稳定性测试中，通过循环伏安法（$C\text{–}V$）计算发现，掺杂后的混合基底上SAM分子的吸附面密度大幅提升了46.8%。第一性原理计算进一步证实，$V_2C\text{-}OH$与SAM分子间的结合能是原生氧化镍的两倍。高温接触角演变实验直观地证明了这种强化学键合的威力，在85°C持续退火48小时后，传统基底上的SAM分子严重解吸附导致疏水性骤降，而混合基底系统仅表现出微小的接触角变化，展现出超凡的热稳定性。

(a) Cyclic voltammograms of NiOx/2PACz and Mixed/2PACz under different voltage scan rates. (b) The relationship between the oxidative peak current and the voltage scan rate for NiOx/2PACz and Mixed/2PACz. (c) The calculated binding energy of 2PACz absorbed on the NiOx and V2C-OH. (d) The water contact angles of NiOx and Mixed, as well as their temporal evolution after being coated with 2PACz and subjected to annealing at 85°C.#

同时，瞬态吸收光谱和电学表征显示，混合薄膜成功清除了因氧化镍复杂缺陷产生的激发态吸收信号，不仅使薄膜电导率由$9.93 \times 10^{-4}\text{ mS/cm}^2$提升至$1.41 \times 10^{-3}\text{ mS/cm}^2$，还通过更深的功函数优化了能级对齐。

(a) Femtosecond transient absorption (fs-TA) spectra at different time delays, (b) high-resolution XPS spectra of Ni 2p3/2, (c) Kelvin probe force microscopy (KPFM) images of NiOx and Mixed films. (d) Ultraviolet photoelectron spectroscopy (UPS) spectra of NiOx/2PACz and Mixed/2PACz. (e) Schematic representation of the band edge positions of HTLs based on values from UPS measurements, referenced to the vacuum level. EVAC and ECBM represent vacuum level and conduction band minimum, respectively (f) I–V curves of ITO/HTLs/Au devices.#

为了进一步可视化电荷提取过程，团队设计了一种独特的双基底沉积策略，在同一块玻璃滑片上同时制备两种薄膜。利用共聚焦激光扫描显微镜（CLSM）和荧光寿命成像，在一瞥之间直接观测到同一块钙钛矿薄膜在混合基底区域展现出极速的荧光猝灭，直接证实了该系统在皮秒级时间尺度上具有更快的激子提取动力学。

(a) Schematic diagram of spin-coating NiOx and Mixed films on two halves of a single glass slide by tape masking. (b) CLSM images and (c) PL mapping of one perovskite film deposited on a film in which NiOx and Mixed coexist. (d) TRPL spectra of perovskite films deposited on glass, NiOx/2PACz, and Mixed/2PACz. (e) fs-TA spectra and (f) corresponding fs-TA spectra at different delay times of perovskite films deposited on NiOx/2PACz and Mixed/2PACz.#

这种高度有序且紧密排列的SAM界面进一步诱导了钙钛矿晶体的规范化生长。扫描电镜（SEM）与广角X射线散射（GIWAXS）分析表明，钙钛矿薄膜的晶粒尺寸明显增大，呈现出有利的垂直取向以及优选的[001]晶面定向排列，近乎完全消除了残余应力导致的晶格畸变，使空间层内部的缺陷态密度骤降。

(a) Top-view and cross-sectional SEM images of NiOx/2PACz/PVK and Mixed/2PACz/PVK. (b) Schematic diagram of charge transport and the morphology of substrate, 2PACz, and perovskite layers. (c) Top-view AFM image and (d) GIWAXS patterns of perovskite films deposited on NiOx/2PACz and Mixed/2PACz. (e) Schematic diagram of randomly oriented and highly oriented perovskite films on NiOx/2PACz and Mixed/2PACz substrates.#

最终的光伏性能测试结果表明，基于该复合空穴传输层的器件实现了26.6%的极限转换效率（认证效率达26.2%），并且在1平方厘米的大面积器件中也稳稳实现了24.7%的高效率。在稳定性方面，未封装的器件在85°C的高温环境下运行1800小时后仍能保持初始效率的90%以上，在常温强光连续照射1600小时后保留了91.21%的效率，表现出极其惊人的耐湿热与光照稳定性。

(a) J–V curves in reverse and forward scanning for 0.0524-cm2 PSCs based on NiOx/2PACz and Mixed/2PACz HTLs. (b) Certified J–V curves for 0.0524-cm2 PSCs based on Mixed/2PACz HTL by Tianjin Institute of Metrological Supervision and Testing (TIMST). (c) J–V curves for 0.0524-cm2 PSCs based on NiOx/2PACz and Mixed/2PACz HTLs. (d) Normalized PCE of unencapsulated devices stored in Ar atmosphere at 85°C. (e) MPP tracking of unencapsulated devices under AM 1.5 simulated solar illumination in ambient atmosphere.#