Hybrid lead halide perovskites have superior charge transport properties to all-inorganic perovskites, but high-resolution spectroscopic radiation detectors have not been realized. Here we show that surface deep traps severely limit charge collection in formamidinium lead bromide (FAPbBr₃) single-crystal devices, despite having a good bulk transport property. Three types of defect on the crystal surface, namely, FA vacancies, uncoordinated lead and Pb–Pb dimers caused by bromide loss, are found to form deep traps, resulting in non-radiative charge recombinations at the metal/perovskite interface. By tailoring the passivation functional groups, we find that ammonium bromide can passivate all these three deep traps on FAPbBr₃ surfaces, improving the charge collection efficiency to near unity. The comparable bulk and surface recombination lifetimes indicate that all the surface defects are effectively passivated. Surface passivation also reduces the dark current by 10 times and decreases the dark counts by ~60 times. The energy resolution of the ¹³⁷Cs spectra acquired using the FAPbBr₃ detectors is improved from 5.7% to 1.7% when all the surface defects are passivated without changing the bulk properties, which is the best among solution-grown semiconductor detectors. Surface passivation is stable for more than six months, and FAPbBr₃ spectroscopic detectors can operate at unprecedented high temperatures of more than 130 °C.

混合卤化铅钙钛矿具有优于全无机钙钛矿的电荷传输特性，但高分辨率光谱辐射探测器尚未实现。在这里，我们表明，尽管甲脒溴化铅（FAPbBr ₃）单晶器件具有良好的整体传输性能，但表面深陷阱严重限制了电荷收集。晶体表面的三种缺陷，即FA空位、不配位的铅和溴化物损失引起的Pb-Pb二聚体，被发现形成深陷阱，导致金属/钙钛矿界面处的非辐射电荷复合。通过定制钝化官能团，我们发现溴化铵可以钝化FAPbBr ₃表面上的所有这三个深陷阱，将电荷收集效率提高到接近一致。相当的体积和表面复合寿命表明所有表面缺陷都被有效钝化。表面钝化还可将暗电流降低 10 倍，并将暗计数降低约 60 倍。当所有表面缺陷都被钝化且不改变体性能时，使用FAPbBr _{3探测器获得的}¹³⁷ Cs 谱的能量分辨率从 5.7% 提高到 1.7%，这是溶液生长半导体探测器中最好的。表面钝化可稳定六个月以上，FAPbBr ₃光谱探测器可在超过 130 °C 的前所未有的高温下运行。