Carrier transport in colloidal quantum dot (CQD) films is strongly influenced by the interfacial coupling between CQDs. Currently, the shape of PbS CQDs synthesized using traditional methods results in random orientation relationships between the crystal facets in CQD films, limiting the coupling strength and the final performance of optoelectronic devices. In this study, post-synthesis surface treatment of PbS CQDs was employed to achieve facet control during secondary growth, manipulating the facets of PbS CQDs at the nanoscale to enhance interfacial coupling within CQD films. Additionally, mixed ligands of PbX2 (X = Br, I) and anhydrous sodium acetate were used to passivate the PbS CQDs, ensuring sufficient passivation. This method combines facet passivation with strong coupling through the (100) facets of CQDs, thereby enhancing carrier mobility and improving device performance. Experimental results showed that, compared to standard PbS CQD films, the electron and hole mobilities of the PbS CQD films subjected to secondary growth were significantly improved, with hole mobility increased by 6 times. Photodetectors fabricated using these films achieved a quantum efficiency of 33% at 1500 nm under 0 V bias, a threefold improvement compared to standard devices.
Tang, J.; Zheng, Y.; Jiang, K.; You, Q.; Yin, Z. T.; Xie, Z. H.; Li, H. N.; Han, C.; Zhang, X. X.; Shi, Y. M. Interlayer exciton dynamics of transition metal dichalcogenide heterostructures under electric fields. Nano Res. 2024, 17, 4555–4572.
Wu, Z. X.; Ou, Y. D.; Cai, M. Q.; Wang, Y. H.; Tang, R. X. ; Xia, Y. Short‐wave infrared photodetectors and imaging sensors based on lead chalcogenide colloidal quantum dots. Adv. Opt. Mater. 2022, 11, 2201577.
Zhou, B.; Liu, Z. X.; Fang, S. F.; Zhong, H. Z.; Tian, B. B.; Wang, Y.; Li, H. N.; Hu, H. L.; Shi, Y. M. Efficient white photoluminescence from self-trapped excitons in Sb3+/Bi3+-codoped Cs2NaInCl6 double perovskites with tunable dual-emission. ACS Energy Lett. 2021, 6, 3343–3351.
Zhou, B.; Du, A. X.; Ding, D.; Liu, Z. X.; Wang, Y.; Zhong, H. Z.; Li, H. N.; Hu, H. L.; Shi, Y. M. Achieving tunable cold/warm white-light emission in a single perovskite material with near-unity photoluminescence quantum yield. Nano-Micro Lett. 2023, 15, 207.
Zhao, X. C.; Li, X. M.; Liu, M.; Zhao, Z. J.; Yang, K. X.; Liu, P. T.; Zhang, H. L.; Li, J. T.; Ma, X. L.; Yao, Q. et al. Photomultiplication-type all-polymer photodetectors and their applications in photoplethysmography sensor. Acta Phys.-Chim. Sin. 2024, 41, 100007.
Zhang, H. L.; Liu, M.; Zhao, X. C.; Ma, X. L.; Yuan, G. C.; Li, J. M.; Zhang, F. J. Photomultiplication type quasi-planar all-polymer photodetectors with tunable response range. Appl. Phys. Lett. 2023, 123, 111101.
Wang, C.; Wang, Y. L.; Jia, Y. W.; Wang, H.; Li, X. F.; Liu, S.; Liu, X. L.; Zhu, H. B.; Wang, H. Y.; Liu, Y. C. et al. Precursor chemistry enables the surface ligand control of PbS quantum dots for efficient photovoltaics. Adv. Sci. 2023, 10, 2204655.
Biondi, M.; Choi, M. J.; Wang, Z. B.; Wei, M. Y.; Lee, S.; Choubisa, H.; Sagar, L. K.; Sun, B.; Baek, S. W.; Chen, B. et al. Facet-oriented coupling enables fast and sensitive colloidal quantum dot photodetectors. Adv. Mater. 2021, 33, 2101056.
Wang, Y. J.; Lu, K. Y.; Han, L.; Liu, Z. K.; Shi, G. Z.; Fang, H. H.; Chen, S.; Wu, T.; Yang, F.; Gu, M. F. et al. In situ passivation for efficient PbS quantum dot solar cells by precursor engineering. Adv. Mater. 2018, 30, 1704871.
Lee, S.; Choi, M. J.; Sharma, G.; Biondi, M.; Chen, B.; Baek, S. W.; Najarian, A. M.; Vafaie, M.; Wicks, J.; Sagar, L. K. et al. Orthogonal colloidal quantum dot inks enable efficient multilayer optoelectronic devices. Nat. Commun. 2020, 11, 4814.
Choi, M. J.; Kim, Y.; Lim, H.; Alarousu, E.; Adhikari, A.; Shaheen, B. S.; Kim, Y. H.; Mohammed, O. F.; Sargent, E. H.; Kim, J. Y. et al. Tuning solute- redistribution dynamics for scalable fabrication of colloidal quantum-dot optoelectronics. Adv. Mater. 2019, 31, 1805886.
Zhang, J. B.; Gao, J. B.; Church, C. P.; Miller, E. M.; Luther, J. M.; Klimov, V. I.; Beard, M. C. PbSe quantum dot solar cells with more than 6% efficiency fabricated in ambient atmosphere. Nano Lett. 2014, 14, 6010–6015.
Kim, Y.; Che, F. L.; Jo, J. W.; Choi, J.; García de Arquer, F. P.; Voznyy, O.; Sun, B.; Kim, J.; Choi, M. J.; Quintero-Bermudez, R. et al. A facet-specific quantum dot passivation strategy for colloid management and efficient infrared photovoltaics. Adv. Mater. 2019, 31, 1805580.
Fu, J. H.; Min, J. C.; Chang, C. K.; Tseng, C. C.; Wang, Q. X.; Sugisaki, H.; Li, C. Y.; Chang, Y. M.; Alnami, I.; Syong, W. R. et al. Oriented lateral growth of two-dimensional materials on c-plane sapphire. Nat. Nanotechnol. 2023, 18, 1289–1294.
Gan, J.; Yu, M.; Hoye, R. L. Z.; Musselman, K. P.; Li, Y.; Liu, X.; Zheng, Y.; Zu, X.; Li, S.; MacManus-Driscoll, J. L. et al. Defects, photophysics and passivation in Pb-based colloidal quantum dot photovoltaics. Mater. Today Nano 2021, 13, 100101.
Hu, L.; Lei, Q.; Guan, X. W.; Patterson, R.; Yuan, J. Y.; Lin, C. H.; Kim, J.; Geng, X.; Younis, A.; Wu, X. X. et al. Optimizing surface chemistry of PbS colloidal quantum dot for highly efficient and stable solar cells via chemical binding. Adv. Sci. 2021, 8, 2003138.
Huang, T. Z.; Wu, C. Y.; Yang, J. P.; Hu, P. Y.; Qian, L.; Sun, T.; Xiang, C. Y. Reducing the open-circuit voltage loss of PbS quantum dot solar cells via hybrid ligand exchange treatment. ACS Appl. Mater. Interfaces 2024, 16, 915–923.
Xia, Y.; Chen, W.; Zhang, P.; Liu, S. S.; Wang, K.; Yang, X. K.; Tang, H. D.; Lian, L. Y.; He, J. G.; Liu, X. X. et al. Facet control for trap-state suppression in colloidal quantum dot solids. Adv. Funct. Mater. 2020, 30, 2000594.
Yang, J. R.; Lu, S. C.; Xia, B.; Liu, P. L.; Yang, Y.; Xiao, Z. W.; Zhang, J. B.; Gao, L.; Tang, J. Excess PbBr2 passivation of large PbS colloidal quantum dots to reduce dark-current density for near-infrared detection. Phys. Rev. Appl. 2023, 19, 014021.
Wang, Y.; Hu, H. C.; Yuan, M. H.; Xia, H.; Zhang, X. C.; Liu, J.; Yang, J.; Xu, S. Q.; Shi, Z. R.; He, J. G. et al. Colloidal PbS quantum dot photodiode imager with suppressed dark current. ACS Appl. Mater. Interfaces 2023, 15, 58573–58582.
Voznyy, O.; Zhitomirsky, D.; Stadler, P.; Ning, Z. J.; Hoogland, S.; Sargent, E. H. A charge-orbital balance picture of doping in colloidal quantum dot solids. ACS Nano 2012, 6, 8448–8455.
Kim, D.; Kim, D. H.; Lee, J. H.; Grossman, J. C. Impact of stoichiometry on the electronic structure of PbS quantum dots. Phys. Rev. Lett. 2013, 110, 196802.
Breen, L. I.; Garner, A. L. Collisional space-charge-limited current with monoenergetic velocity: From child-Langmuir to Mott-gurney. Phys. Plasmas 2024, 31, 032102.
Fang, F. E.; Wan, Y.; Li, H. N.; Fang, S. F.; Huang, F.; Zhou, B.; Jiang, K.; Tung, V.; Li, L. J.; Shi, Y. M. Two-dimensional Cs2AgBiBr6/WS2 heterostructure-based photodetector with boosted detectivity via interfacial engineering. ACS Nano 2022, 16, 3985–3993.
Yu, S. Q.; Xiong, Z.; Zhou, H. T.; Zhang, Q.; Wang, Z. H.; Ma, F.; Qu, Z. H.; Zhao, Y.; Chu, X. B.; Zhang, X. W. et al. Homogenized NiO x nanoparticles for improved hole transport in inverted perovskite solar cells. Science 2023, 382, 1399–1404.
Zhang, L.; Chen, Y.; Cao, S.; Yuan, D. F.; Tang, X.; Wang, D. K.; Gao, Y. J.; Zhang, J. J.; Zhao, Y. B.; Yang, X. C. et al. Interfacial heterojunction enables high efficient PbS quantum dot solar cells. Adv. Sci. 2024, 11, 2402756.
Sun, B.; Vafaie, M.; Levina, L.; Wei, M. Y.; Dong, Y. T.; Gao, Y. J.; Kung, H. T.; Biondi, M.; Proppe, A. H.; Chen, B. et al. Ligand-assisted reconstruction of colloidal quantum dots decreases trap state density. Nano Lett. 2020, 20, 3694–3702.
Ding, C.; Liu, F.; Zhang, Y. H.; Hayase, S.; Masuda, T.; Wang, R. X.; Zhou, Y.; Yao, Y. F.; Zou, Z. G.; Shen, Q. Passivation strategy of reducing both electron and hole trap states for achieving high-efficiency PbS quantum-dot solar cells with power conversion efficiency over 12%. ACS Energy Lett. 2020, 5, 3224–3236.
Goossens, V. M.; Sukharevska, N. V.; Dirin, D. N.; Kovalenko, M. V.; Loi, M. A. Scalable fabrication of efficient p-n junction lead sulfide quantum dot solar cells. Cell Rep. Phys. Sci. 2021, 2, 100655.
Ding, C.; Wang, D. D.; Liu, D.; Li, H.; Li, Y. S.; Hayase, S.; Sogabe, T.; Masuda, T.; Zhou, Y.; Yao, Y. F. et al. Over 15% efficiency PbS quantum-dot solar cells by synergistic effects of three interface engineering: Reducing nonradiative recombination and balancing charge carrier extraction. Adv. Energy Mater. 2022, 12, 2201676.
Zhang, Y. H.; Wu, G. H.; Liu, F.; Ding, C.; Zou, Z. G.; Shen, Q. Photoexcited carrier dynamics in colloidal quantum dot solar cells: Insights into individual quantum dots, quantum dot solid films and devices. Chem. Soc. Rev. 2020, 49, 49–84.
Xiao, G. N.; Liang, T. H.; Wang, X. M.; Ying, C.; Lv, K.; Shi, C. W. Reduced surface trap states of PbS quantum dots by acetonitrile treatment for efficient SnO2-based PbS quantum dot solar cells. ACS Omega 2024, 9, 12211–12218.
Mao, C. H.; Dubey, A.; Lee, F. J.; Chen, C. Y.; Tang, S. Y.; Ranjan, A.; Lu, M. Y.; Chueh, Y. L.; Gwo, S.; Yen, T. J. An ultrasensitive gateless photodetector based on the 2D bilayer MoS2-1D Si nanowire-0D Ag nanoparticle hybrid structure. ACS Appl. Mater. Interfaces 2021, 13, 4126–4132.
Fu, Y. J.; Wang, Y. J.; Zhao, J. J.; Wen, S.; Liu, H.; Li, Q.; Gu, B. A.; Deng, L. E. Size-tunable and monodisperse lead sulfide quantum dots for broadband photodetectors. APL Mater. 2024, 12, 031126.
Zhang, L. X.; Chen, L.; Yang, J. R.; Liu, J.; Lu, S. C.; Liang, X. Y.; Zhao, X. Z.; Yang, Y.; Hu, J.; Hu, L. et al. High-performance and stable colloidal quantum dots imager via energy band engineering. Nano Lett. 2023, 23, 6489–6496.
Liu, J.; Liu, P. L.; Chen, D. Y.; Shi, T. L.; Qu, X. X.; Chen, L.; Wu, T.; Ke, J. P.; Xiong, K.; Li, M. Y. et al. A near-infrared colloidal quantum dot imager with monolithically integrated readout circuitry. Nat. Electron. 2022, 5, 443–451.
Lu, S. C.; Liu, P. L.; Yang, J. R.; Liu, S. J.; Yang, Y.; Chen, L.; Liu, J.; Liu, Y. X.; Wang, B.; Lan, X. Z. et al. High-performance colloidal quantum dot photodiodes via suppressing interface defects. ACS Appl. Mater. Interfaces 2023, 15, 12061–12069.
Hines, M. A.; Scholes, G. D. Colloidal PbS nanocrystals with size-tunable near-infrared emission: Observation of post-synthesis self-narrowing of the particle size distribution. Adv. Mater. 2003, 15, 1844–1849.