Core-shell structure induced surface reconstruction of PbS quantum dots toward high-detectivity short-wave infrared photodetectors

Abstract

Surface passivation and reconstruction in quantum dot (QD) materials are crucial for enhancing the performance of optoelectronic devices, particularly in high-sensitivity, low-noise short-wave infrared (SWIR) photodetectors (PDs). This study presents an optimized approach for PbS/CdS core-shell QDs through optimized surface engineering through controlled CdS shell modulation and solution-phase ligand exchange with concentrated lead halides. The refined surface reconstruction significantly reduces QD aggregation and reduces trap states, resulting in ordered QD stackings with narrower energy distributions. Consequently, the QD PDs achieve a significantly reduced dark current density of 192 nA cm⁻² and an enhanced detectivity of 5.06 × 10¹² Jones, resulting in a 29.6% reduction in dark current and a 7.4-fold improvement in detectivity compared to pristine QD PDs. Electrochemical impedance spectroscopy confirms the reduction in trap-assisted recombination, supported by extended photoluminescence lifetimes and higher quantum efficiencies. These findings underscore the potential of surface reconstructed QDs for advanced SWIR PD applications, particularly in achieving high sensitivity in imaging systems.

Keywords

GISAXS / photodetector / quantum dots / short-wave infrared / surface reconstruction

References

[1] Liu J, Liu P, Chen D, et al. A near-infrared colloidal quantum dot imager with monolithically integrated readout circuitry. Nat Electron. 2022;5(7):443-451.

[2] Liu Y, Liu J, Deng C, et al. Planar cation passivation on colloidal quantum dots enables high-performance 0.35–1.8 μm broadband TFT imager. Adv Mater. 2024;36(21):e2313811.

[3] Mu G, Tan Y, Bi C, Liu Y, Hao Q, Tang X. Visible to mid-wave infrared PbS/HgTe colloidal quantum dot imagers. Nat Photonics. 2024;18(11):1147-1154.

[4] Pejovic V, Georgitzikis E, Lee J, et al. Infrared colloidal quantum dot image sensors. IEEE Trans Electron Dev. 2022;69(6):2840-2850.

[5] Wang Y, Peng L, Schreier J, et al. Silver telluride colloidal quantum dot infrared photodetectors and image sensors. Nat Photonics. 2024;18(3):236-242.

[6] Zhang Y, Xia P, Rehl B, et al. Dicarboxylic acid-assisted surface oxide removal and passivation of indium antimonide colloidal quantum dots for short-wave infrared photodetectors. Angew Chem Int Ed. 2024;63(8):e202316733.

[7] Ban HW, Vafaie M, Levina L, et al. Resurfacing of InAs colloidal quantum dots equalizes photodetector performance across synthetic routes. J Am Chem Soc. 2024;146(36):24935-24944.

[8] Peng L, Wang Y, Ren Y, Wang Z, Cao P, Konstantatos G. InSb/InP core–shell colloidal quantum dots for sensitive and fast short-wave infrared photodetectors. ACS Nano. 2024;18(6):5113-5121.

[9] Wang B, Yuan M, Liu J, et al. Synergism in binary nanocrystals enables top-illuminated HgTe colloidal quantum dot short-wave infrared imager. Nano Lett. 2024;24(31):9583-9590.

[10] Shin D, Jeong H, Kim J, Jang E, Park Y, Jeong S. High performance infrared InAs colloidal quantum dot photodetector with 79% EQE enabled by an extended absorber layer. Adv Opt Mater. 2024;13(1):2401931.

[11] Kim G, Choi D, Eom SY, et al. Extended short-wavelength infrared ink by surface-tuned silver telluride colloidal quantum dots and their infrared photodetection. ACS Mater Lett. 2024;6(11):4988-4996.

[12] Ahn Y, Eom SY, Kim G, et al. Silver telluride colloidal quantum dot solid for fast extended shortwave infrared photodetector. Adv Sci. 2024;11(44):e2407453.

[13] Leemans J, Pejović V, Georgitzikis E, et al. Colloidal III–V quantum dot photodiodes for short-wave infrared photodetection. Adv Sci. 2022;9(17):2200844.

[14] Zhang S, Bi C, Qin T, et al. Wafer-scale fabrication of CMOS-compatible trapping-mode infrared imagers with colloidal quantum dots. ACS Photonics. 2023;10(3):673-682.

[15] Lee JA, Lee IS, Kang D, et al. Chemical reactivity-controlled synthesis of silver chalcogenide colloidal quantum dots for efficient shortwave infrared photodetectors. Small. 2025;21(20):2412420.

[16] Jee S, Si MJ, Choi JH, et al. P-Type colloidal InSb quantum dot ink enables III–V group bulk-heterojunction shortwave infrared (SWIR) photodetector. Adv Opt Mater. 2024;12(18):2303097.

[17] Si MJ, Jee S, Yang M, et al. Colloidal InAs quantum dot-based infrared optoelectronics enabled by universal dual-ligand passivation. Adv Sci. 2024;11(13):2306798.

[18] Chen W, Zhong J, Li J, et al. Structure and charge carrier dynamics in colloidal PbS quantum dot solids. J Phys Chem Lett. 2019;10(9):2058-2065.

[19] Wang C, Wang Y, Jia Y, et al. Precursor chemistry enables the surface ligand control of PbS quantum dots for efficient photovoltaics. Adv Sci. 2022;10(4):e2204655.

[20] Xiao T, Tu S, Tian T, et al. Autonomous self-healing hybrid energy harvester based on the combination of triboelectric nanogenerator and quantum dot solar cell. Nano Energy. 2024;125:109555.

[21] Wang Y, Liu Z, Huo N, et al. Room-temperature direct synthesis of semi-conductive PbS nanocrystal inks for optoelectronic applications. Nat Commun. 2019;10(1):5136.

[22] Jung Y, Shin H, Baek S-W, et al. Near-unity broadband quantum efficiency enabled by colloidal quantum dot/mixed-organic heterojunction. ACS Energy Lett. 2023;8(5):2331-2337.

[23] Kim D, Cho G, Kim YH, et al. Multi-facet passivation of ternary colloidal quantum dot enabled by quadruple-ligand ensemble toward efficient lead-free optoelectronics. Adv Energy Mater. 2024;14(7):2302579.

[24] Zhang L, Han Z, Wang S, et al. Indeno[1,2-b]carbazole-Based hole conductor enables a high-performance colloidal quantum dot NIR photodetector. ACS Photonics. 2024;11(8):3309-3316.

[25] Zhang L, Chen Y, Cao S, et al. Interfacial heterojunction enables high efficient PbS quantum dot solar cells. Adv Sci. 2024;11(26):2402756.

[26] Xia H, Hu H, Wang Y, et al. Ligand-customized colloidal quantum dots for high-performance optoelectronic devices. J Mater Chem C. 2024;12(29):10919-10928.

[27] Liu P, Lu S, Liu J, et al. Double-ended passivator enables dark-current-suppressed colloidal quantum dot photodiodes for CMOS-integrated infrared imagers. InfoMat. 2023;6(1):e12497.

[28] Sun B, Vafaie M, Levina L, et al. Ligand-assisted reconstruction of colloidal quantum dots decreases trap state density. Nano Lett. 2020;20(5):3694-3702.

[29] Sun B, Johnston A, Xu C, et al. Monolayer perovskite bridges enable strong quantum dot coupling for efficient solar cells. Joule. 2020;4(7):1542-1556.

[30] Chen D, Liu Y, Xia B, et al. Passivating {100} facets of PbS colloidal quantum dots via perovskite bridges for sensitive and stable infrared photodiodes. Adv Funct Mater. 2022;33(1):2210158.

[31] Wang H, Pinna J, Romero DG, et al. PbS quantum dots ink with months-long shelf-lifetime enabling scalable and efficient short-wavelength infrared photodetectors. Adv Mater. 2024;36(19):e2311526.

[32] Chen H, Pina JM, Hou Y, Sargent EH. Synthesis, applications, and prospects of quantum-dot-in-perovskite solids. Adv Energy Mater. 2021;12(4):2100774.

[33] Vafaie M, Fan JZ, Morteza Najarian A, et al. Colloidal quantum dot photodetectors with 10-ns response time and 80% quantum efficiency at 1,550 nm. Matter. 2021;4(3):1042-1053.

[34] Zhao X, Li M, Ma T, et al. Stable PbS colloidal quantum dot inks enable blade-coating infrared solar cells. Front Optoelectron. 2023;16(1):27.

[35] Kim Y, Che F, Jo JW, et al. A facet-specific quantum dot passivation strategy for colloid management and efficient infrared photovoltaics. Adv Mater. 2019;31(17):e1805580.

[36] Fan JZ, Andersen NT, Biondi M, et al. Mixed lead halide passivation of quantum dots. Adv Mater. 2019;31(48):e1904304.

[37] Xu J, Voznyy O, Liu M, et al. 2D matrix engineering for homogeneous quantum dot coupling in photovoltaic solids. Nat Nanotechnol. 2018;13(6):456-462.

[38] Sandberg OJ, Sundqvist A, Nyman M, Österbacka R. Relating charge transport, contact properties, and recombination to open-circuit voltage in sandwich-type thin-film solar cells. Phys Rev Appl. 2016;5(4):044005.

[39] Yang QK, Fuchs F, Schmitz J, Pletschen W. Investigation of trap-assisted tunneling current in InAs/(GaIn)Sb superlattice long-wavelength photodiodes. Appl Phys Lett. 2002;81(25):4757-4759.

[40] Parmar DH, Rehl B, Atan O, Hoogland S, Sargent EH. Transient measurements and simulations correlate exchange ligand concentration and trap states in colloidal quantum dot photodetectors. ACS Appl Mater Interfaces. 2023;15(51):59931-59938.

[41] Albaladejo-Siguan M, Becker-Koch D, Baird EC, et al. Interdot lead halide excess management in PbS quantum dot solar cells. Adv Energy Mater. 2022;12(45):2202994.

[42] Ye Y, Liu S, Lei H, et al. Suppressed magnitude of spectral diffusion in cube-shaped CdSe/CdS core/shell nanocrystals with exceedingly stable photoluminescence. Nano Lett. 2024;24(9):2712-2718.

[43] Sun H, Cao Z, Qin H, Peng X, Su B. Ligand-controlled electrochemiluminescence generation from CdSe/CdS/ZnS core/shell/shell quantum dots. Nano Res. 2024;17(8):7776-7785.

[44] Cao Z, Li C, Shu Y, et al. Unraveling mechanisms of highly efficient yet stable electrochemiluminescence from quantum dots. J Am Chem Soc. 2023;145(48):26425-26434.

[45] Zhang W, Tan Y, Duan X, et al. High quantum yield blue InP/ZnS/ZnS quantum dots based on bromine passivation for efficient blue light-emitting diodes. Adv Opt Mater. 2022;10(15):2200685.

[46] Chen W, Wang K, Hao J, et al. High efficiency and color rendering quantum dots white light emitting diodes optimized by luminescent microspheres incorporating. Nanophotonics. 2016;5(4):565-572.

[47] Speirs MJ, Balazs DM, Fang HH, et al. Origin of the increased open circuit voltage in PbS–CdS core–shell quantum dot solar cells. J Mater Chem A. 2015;3(4):1450-1457.

[48] Colbert AE, Placencia D, Ratcliff EL, et al. Enhanced infrared photodiodes based on PbS/PbCl_x core/shell nanocrystals. ACS Appl Mater Interfaces. 2021;13(49):58916-58926.

[49] Neo DCJ, Cheng C, Stranks SD, et al. Influence of shell thickness and surface passivation on PbS/CdS core/shell colloidal quantum dot solar cells. Chem Mater. 2014;26(13):4004-4013.

[50] Nasilowski M, Nienhaus L, Bertram SN, Bawendi MG. Colloidal atomic layer deposition growth of PbS/CdS core/shell quantum dots. Chem Commun. 2017;53(5):869-872.

[51] Lechner RT, Fritz-Popovski G, Yarema M, et al. Crystal phase transitions in the shell of PbS/CdS core/shell nanocrystals influences photoluminescence intensity. Chem Mater. 2014;26(20):5914-5922.

[52] Son DH, Hughes SM, Yin Y, Paul Alivisatos A. Cation exchange reactions in ionic nanocrystals. Science. 2004;306(5698):1009-1012.

[53] Beberwyck BJ, Surendranath Y, Alivisatos AP. Cation exchange: a versatile tool for nanomaterials synthesis. J Phys Chem C. 2013;117(39):19759-19770.

[54] Lee EMY, Tisdale WA. Determination of exciton diffusion length by transient photoluminescence quenching and its application to quantum dot films. J Phys Chem C. 2015;119(17):9005-9015.

[55] Buffet A, Rothkirch A, Döhrmann R, et al. P03, the microfocus and nanofocus X-ray scattering (MiNaXS) beamline of the PETRA III storage ring: the microfocus endstation. J Synchrotron Radiat. 2012;19(Pt 4):647-653.

[56] Chen W, Guo R, Tang H, et al. Operando structure degradation study of PbS quantum dot solar cells. Energy Environ Sci. 2021;14(6):3420-3429.

[57] Breßler I, Kohlbrecher J, Thünemann AF. SASfit: a tool for small-angle scattering data analysis using a library of analytical expressions. J Appl Crystallogr. 2015;48(5):1587-1598.

[58] Wang Y, Hu H, Ran X, et al. Electrode engineering of colloidal quantum dot photodetectors using a self-assembled island-like LiF interfacial layer. ACS Photonics. 2024;11(4):1734-1742.

[59] Deng YH, Pang C, Kheradmand E, et al. Short-wave infrared colloidal QD photodetector with nanosecond response times enabled by ultrathin absorber layers. Adv Mater. 2024;36(28):2402002.

[60] Wang Y, Hu H, Yuan M, et al. Colloidal PbS quantum dot photodiode imager with suppressed dark current. ACS Appl Mater Interfaces. 2023;15(50):58573-58582.

[61] Zhang L, Chen L, Yang J, et al. High-performance and stable colloidal quantum dots imager via energy band engineering. Nano Lett. 2023;23(14):6489-6496.

[62] Lu S, Liu P, Yang J, et al. High-performance colloidal quantum dot photodiodes via suppressing interface defects. ACS Appl Mater Interfaces. 2023;15(9):12061-12069.

[63] Liang X, Liu Y, Liu P, et al. Large-area flexible colloidal-quantum-dot infrared photodiodes for photoplethysmogram signal measurements. Sci Bull. 2023;68(7):698-705.

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