{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T14:51:50Z","timestamp":1786632710923,"version":"build-2736575974"},"reference-count":49,"publisher":"American Chemical Society (ACS)","issue":"32","license":[{"start":{"date-parts":[[2026,7,29]],"date-time":"2026-07-29T00:00:00Z","timestamp":1785283200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100007062","name":"Yangzhou University","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100007062","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Swedish Government Strategic Research Area in Materials Science on Functional Materials at Link\u00f6ping University","award":["2009 00971"],"award-info":[{"award-number":["2009 00971"]}]},{"name":"Science and Technology on Metrology and Calibration Laboratory","award":["JLKG2023001C007"],"award-info":[{"award-number":["JLKG2023001C007"]}]},{"name":"Science and Technology on Metrology and Calibration Laboratory","award":["JLKG2024001C004"],"award-info":[{"award-number":["JLKG2024001C004"]}]},{"name":"Swedish Research Council (VR)","award":["2022-04818"],"award-info":[{"award-number":["2022-04818"]}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China (NSFC)","doi-asserted-by":"crossref","award":["62375234"],"award-info":[{"award-number":["62375234"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,8,13]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Alkali-metal incorporation is widely employed to improve the performance and stability of organic halide perovskites, yet the underlying doping mechanisms and diffusion pathways remain poorly understood. Here, we use ultraviolet photoemission spectroscopy to probe the evolution of the electronic structure of CH3NH3PbX3 (X = I, Br, and Cl) single crystals upon potassium and cesium deposition. We observe two distinct regimes governed by halide chemistry: facile bulk diffusion in CH3NH3PbI3 and CH3NH3PbBr3, in contrast to surface-confined accumulation in CH3NH3PbCl3, arising from kinetically hindered alkali migration in the chloride perovskite. Temperature-dependent measurements of the doped crystals further detect opposite valence band shifts for CH3NH3PbBr3 relative to CH3NH3PbI3 and CH3NH3PbCl3, highlighting the role of surface termination and charge redistribution. Notably, alkali metal deposition induces substantial energy level shifts while leaving band dispersions largely unchanged, indicating a predominantly interfacial doping mechanism. These results establish a direct link among halide composition, diffusion behavior, and electronic structure evolution, providing microscopic insight into alkali-metal interactions in perovskites.<\/jats:p>","DOI":"10.1021\/acs.jpclett.6c01932","type":"journal-article","created":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T17:06:32Z","timestamp":1785431192000},"page":"9448-9456","source":"Crossref","is-referenced-by-count":0,"title":["Evolution of\nthe Electronic Structure of Hybrid Organic\u2013Inorganic\nHalide Perovskite Single Crystals upon Alkali Metal Doping"],"prefix":"10.1021","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1887-1675","authenticated-orcid":true,"given":"Jinpeng","family":"Yang","sequence":"first","affiliation":[{"name":"Yangzhou University , , ,","place":["Jiangsu, China, 225009"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tingyu","family":"Jiao","sequence":"additional","affiliation":[{"name":"China Institute of Atomic Energy , , ,","place":["Beijing, China, 102413"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wei","family":"Li","sequence":"additional","affiliation":[{"name":"China Institute of Atomic Energy , , ,","place":["Beijing, China, 102413"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bo","family":"Xu","sequence":"additional","affiliation":[{"name":"China Pharmaceutical University , , , ,","place":["Nanjing, China, 211198"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9879-3915","authenticated-orcid":true,"given":"Mats","family":"Fahlman","sequence":"additional","affiliation":[{"name":"Linko\u0308ping University , , ,","place":["Norrko\u0308ping, Sweden, SE-60174"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0353-5863","authenticated-orcid":true,"given":"Satoshi","family":"Kera","sequence":"additional","affiliation":[{"name":"Institute for Molecular Science , Myodaiji , ,","place":["Okazaki, Japan, 444-8585"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3190-2774","authenticated-orcid":true,"given":"Xianjie","family":"Liu","sequence":"additional","affiliation":[{"name":"Linko\u0308ping University , , ,","place":["Norrko\u0308ping, Sweden, SE-60174"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"316","published-online":{"date-parts":[[2026,7,29]]},"reference":[{"key":"2026081310071277700_cit1","unstructured":"National renewable energy laboratory.\n          . 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Soc.\nRev."},{"key":"2026081310071277700_cit7","doi-asserted-by":"publisher","first-page":"3","DOI":"10.1038\/s43586-024-00373-9","article-title":"Perovskite solar cells","volume":"5","author":"Han","year":"2025","journal-title":"Nat. Rev. Methods Primers"},{"key":"2026081310071277700_cit8","doi-asserted-by":"publisher","first-page":"4915","DOI":"10.1021\/acsenergylett.3c01935","article-title":"Single-Crystal\nMethylammonium-Free Perovskite Solar Cells with Efficiencies Exceeding\n24% and High Thermal Stability","volume":"8","author":"Lintangpradipto","year":"2023","journal-title":"ACS Energy Lett."},{"key":"2026081310071277700_cit9","doi-asserted-by":"publisher","first-page":"143019","DOI":"10.1016\/j.cej.2023.143019","article-title":"Single crystal Perovskite-Based\nsolar Cells: Growth, Challenges, and potential strategies","volume":"466","author":"Pandey","year":"2023","journal-title":"Chem. Eng. 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Commun."},{"key":"2026081310071277700_cit13","doi-asserted-by":"publisher","first-page":"497","DOI":"10.1038\/nature25989","article-title":"Maximizing and stabilizing luminescence from halide\nperovskites with potassium passivation","volume":"555","author":"Abdi-Jalebi","year":"2018","journal-title":"Nature"},{"key":"2026081310071277700_cit14","doi-asserted-by":"publisher","first-page":"2696","DOI":"10.1039\/D0CS01316A","article-title":"Advent of alkali metal\ndoping: a roadmap for the evolution of perovskite\nsolar cells","volume":"50","author":"Kausar","year":"2021","journal-title":"Chem. Soc. Rev."},{"key":"2026081310071277700_cit15","doi-asserted-by":"publisher","first-page":"1700131","DOI":"10.1002\/advs.201700131","article-title":"Alkali Metal Doping\nfor Improved CH3NH3PbI3 Perovskite\nSolar Cells","volume":"5","author":"Zhao","year":"2018","journal-title":"Adv. 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Photonics"},{"key":"2026081310071277700_cit17","doi-asserted-by":"publisher","first-page":"967","DOI":"10.1126\/science.aaa5760","article-title":"Electron\u2013Hole\nDiffusion Lengths &gt; 175 \u03bcm\nin Solution-Grown CH3NH3PbI3 Single\nCrystals","volume":"347","author":"Dong","year":"2015","journal-title":"Science"},{"key":"2026081310071277700_cit18","doi-asserted-by":"publisher","first-page":"1352","DOI":"10.1126\/science.aba0893","article-title":"Resolving spatial and energetic distributions of trap states in metal\nhalide perovskite solar cells","volume":"367","author":"Ni","year":"2020","journal-title":"Science"},{"key":"2026081310071277700_cit19","doi-asserted-by":"publisher","first-page":"475001","DOI":"10.1088\/1361-648X\/ac22da","article-title":"Density of gap states\nin CH3NH3PbI3 single crystals probed with ultrahigh-sensitivity ultraviolet\nphotoelectron spectroscopy","volume":"33","author":"Yang","year":"2021","journal-title":"J. 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Lett."},{"key":"2026081310071277700_cit29","doi-asserted-by":"publisher","first-page":"6509","DOI":"10.1021\/jp710197c","article-title":"Electronic properties\nand orbital-filling\nmechanism in Rb-intercalated copper phthalocyanine","volume":"112","author":"Evangelista","year":"2008","journal-title":"J. Phys. Chem. C"},{"key":"2026081310071277700_cit30","doi-asserted-by":"publisher","first-page":"2382","DOI":"10.1021\/jp203572z","article-title":"Electronic Band and\nOrbital Properties of Cs-Doped Pentacene Thin Films","volume":"116","author":"Annese","year":"2012","journal-title":"J. Phys. Chem. C"},{"key":"2026081310071277700_cit31","doi-asserted-by":"publisher","first-page":"1707350","DOI":"10.1002\/adma.201707350","article-title":"Interstitial\nOccupancy by Extrinsic Alkali Cations in Perovskites and Its Impact\non Ion Migration","volume":"30","author":"Cao","year":"2018","journal-title":"Adv. Mater."},{"key":"2026081310071277700_cit32","doi-asserted-by":"publisher","first-page":"117","DOI":"10.1016\/j.cplett.2019.05.050","article-title":"Fabrication and evaluation\nof K-doped (CH3NH3)0.8(HC(NH2)2)0.1K0.1PbI3(Cl) perovskite solar cells","volume":"730","author":"Machiba","year":"2019","journal-title":"Chem. Phys. Lett."},{"key":"2026081310071277700_cit33","doi-asserted-by":"publisher","first-page":"436","DOI":"10.1016\/j.ceramint.2021.09.119","article-title":"Lattice relaxation\neffect in CsxMA(1-x)PbBr3 single crystal to enhance optoelectronic\nperformance of perovskite photodetectors","volume":"48","author":"Li","year":"2022","journal-title":"Ceram.\nInt."},{"key":"2026081310071277700_cit34","doi-asserted-by":"publisher","first-page":"935","DOI":"10.1016\/0022-3697(92)90121-S","article-title":"Dielectric\nstudy of CH3NH3PbX3 (X\n= Cl, Br, I)","volume":"53","author":"Onoda-Yamamuro","year":"1992","journal-title":"J. Phys. Chem. Solids"},{"key":"2026081310071277700_cit35","doi-asserted-by":"publisher","first-page":"22428","DOI":"10.1021\/jp4032089","article-title":"Experimental Study\nof the Electronic Structure and Electron\u2013Phonon Coupling of\nthe Perfluoropentacene Monolayer on Graphite","volume":"117","author":"Kera","year":"2013","journal-title":"J. Phys. Chem. C"},{"key":"2026081310071277700_cit36","doi-asserted-by":"publisher","first-page":"958","DOI":"10.1021\/acs.chemmater.6b03259","article-title":"Influence of Surface Termination\non the Energy Level Alignment at the CH3NH3PbI3 Perovskite\/C60 Interface","volume":"29","author":"Quarti","year":"2017","journal-title":"Chem. Mater."},{"key":"2026081310071277700_cit37","doi-asserted-by":"publisher","first-page":"245101","DOI":"10.1103\/PhysRevB.102.245101","article-title":"Temperature-dependent band structure\nevolution determined by the\norganic cation dynamics in hybrid halide perovskites","volume":"102","author":"Yang","year":"2020","journal-title":"Phys. Rev. B"},{"key":"2026081310071277700_cit38","doi-asserted-by":"publisher","first-page":"011009","DOI":"10.7567\/1882-0786\/ab6134","article-title":"Valence band dispersion\nmeasured in the surface normal direction of CH3NH3PbI3 single crystals","volume":"13","author":"Yang","year":"2020","journal-title":"Appl. Phys.\nExpress"},{"key":"2026081310071277700_cit39","doi-asserted-by":"publisher","first-page":"1800132","DOI":"10.1002\/solr.201800132","article-title":"Band Dispersion\nand Hole Effective\nMass of Methylammonium Lead Iodide Perovskite","volume":"2","author":"Yang","year":"2018","journal-title":"Solar RRL"},{"key":"2026081310071277700_cit40","doi-asserted-by":"publisher","first-page":"601","DOI":"10.1021\/acs.jpclett.8b03728","article-title":"Constructing\nthe Electronic Structure\nof CH3NH3PbI3 and CH3NH3PbBr3 Perovskite Thin Films from Single-Crystal\nBand Structure Measurements","volume":"10","author":"Zu","year":"2019","journal-title":"J. Phys. Chem.\nLett."},{"key":"2026081310071277700_cit41","doi-asserted-by":"publisher","first-page":"2004981","DOI":"10.1002\/adma.202004981","article-title":"Surface Termination\nof Solution-Processed CH3NH3PbI3 Perovskite\nFilm Examined using Electron\nSpectroscopies","volume":"33","author":"Mirzehmet","year":"2021","journal-title":"Adv. Mater."},{"key":"2026081310071277700_cit42","doi-asserted-by":"publisher","first-page":"6373","DOI":"10.1063\/1.453467","article-title":"Dynamic disorder in methylammoniumtrihalogenoplumbates (II) observed\nby millimeter-wave spectroscopy","volume":"87","author":"Poglitsch","year":"1987","journal-title":"J. Chem. Phys."},{"key":"2026081310071277700_cit44","doi-asserted-by":"publisher","first-page":"26655","DOI":"10.1021\/acs.jpcc.7b08948","article-title":"Valence Level Character in a Mixed\nPerovskite Material and Determination of the Valence Band Maximum\nfrom Photoelectron Spectroscopy: Variation with Photon Energy","volume":"121","author":"Philippe","year":"2017","journal-title":"J. Phys. Chem. C"},{"key":"2026081310071277700_cit45","doi-asserted-by":"publisher","first-page":"7570","DOI":"10.1021\/acsnano.3c12587","article-title":"Visualizing\nthe Low-Energy Electronic Structure of Prototypical Organic\u2013Inorganic\nHybrid Perovskites","volume":"18","author":"Park","year":"2024","journal-title":"ACS Nano"},{"key":"2026081310071277700_cit46","doi-asserted-by":"publisher","first-page":"16225","DOI":"10.1021\/acsami.8b04182","article-title":"Oxygen- and Water-Induced Energetics Degradation in Organometal Halide\nPerovskites","volume":"10","author":"Yang","year":"2018","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"2026081310071277700_cit47","doi-asserted-by":"publisher","first-page":"7859","DOI":"10.1021\/acsami.7b00312","article-title":"Electronic Structures\nand Energy-Level Alignment with an Organic Hole-Transporting Layer\nof CH3NH3PbI3-xClx Perovskite Thin Films","volume":"9","author":"Wang","year":"2017","journal-title":"ACS Appl. Mater. Interfaces"},{"key":"2026081310071277700_cit48","doi-asserted-by":"publisher","first-page":"4720","DOI":"10.1021\/acs.nanolett.6b02307","article-title":"Dissociation\nof Methylammonium Cations in Hybrid Organic\u2013Inorganic Perovskite\nSolar Cells","volume":"16","author":"Xu","year":"2016","journal-title":"Nano Lett."},{"key":"2026081310071277700_cit49","doi-asserted-by":"publisher","first-page":"3904","DOI":"10.1021\/acs.jpcc.6b11853","article-title":"Light-Induced Degradation ofCH3NH3PbI3\nHybrid Perovskite Thin Film","volume":"121","author":"Li","year":"2017","journal-title":"J. Phys. Chem.\nC"},{"key":"2026081310071277700_cit50","doi-asserted-by":"publisher","first-page":"183303","DOI":"10.1063\/1.3258351","article-title":"Low-density\nband-gap states in pentacene thin films probed with ultrahigh-sensitivity\nultraviolet photoelectron spectroscopy","volume":"95","author":"Sueyoshi","year":"2009","journal-title":"Appl.\nPhys. Lett."}],"container-title":["The Journal of Physical\nChemistry Letters"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pubs.acs.org\/doi\/pdf\/10.1021\/acs.jpclett.6c01932","content-type":"application\/pdf","content-version":"vor","intended-application":"unspecified"},{"URL":"https:\/\/pubs.acs.org\/jpclcd\/article-pdf\/17\/32\/9448\/66333735\/acs.jpclett.6c01932.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/pubs.acs.org\/jpclcd\/article-pdf\/17\/32\/9448\/66333735\/acs.jpclett.6c01932.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T14:14:31Z","timestamp":1786630471000},"score":1,"resource":{"primary":{"URL":"https:\/\/pubs.acs.org\/jpclcd\/article\/17\/32\/9448\/5236955\/Evolution-of-the-Electronic-Structure-of-Hybrid"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,29]]},"references-count":49,"journal-issue":{"issue":"32","published-online":{"date-parts":[[2026,7,29]]},"published-print":{"date-parts":[[2026,8,13]]}},"URL":"https:\/\/doi.org\/10.1021\/acs.jpclett.6c01932","relation":{},"ISSN":["1948-7185"],"issn-type":[{"value":"1948-7185","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,29]]}}}