Improving the Carrier Lifetime of Tin Sulfide via Prediction and Mitigation of Harmful Point Defects

Polizzotti, Alex; Faghaninia, Alireza; Poindexter, Jeremy R.; Nienhaus, Lea; Steinmann, Vera; Hoye, Robert L. Z.; Felten, Alexandre; Deyine, Amjad; Mangan, Niall M.; Shin, Seong Sik; Jaffer, Shaffiq A.; Bawendi, Moungi G.; Lo, Cynthia S.; Buonassisi, Tonio

doi:10.1021/acs.jpclett.7b01406

Cited by 22 publications

(11 citation statements)

References 53 publications

(79 reference statements)

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“…[10]. Additionally, SnS exhibits intrinsic p-type semiconductor characteristics due to tin vacancies [8,11,12]. The crystallization behavior in this experiment was different from our previous reports that directly deposited SnS film by ALD, which showed only a main (111) peak of orthorhombic SnS phase at 31.53° [25].…”

Section: Introductioncontrasting

confidence: 71%

Development of a SnS Film Process for Energy Device Applications

Choi¹,

Lee

Park³

et al. 2019

Applied Sciences

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Tin monosulfide (SnS) is a promising p-type semiconductor material for energy devices. To realize the device application of SnS, studies on process improvement and film characteristics of SnS is needed. Thus, we developed a new film process using atomic layer deposition (ALD) to produce SnS films with high quality and various film characteristics. First, a process for obtaining a thick SnS film was studied. An amorphous SnS2 (a-SnS2) film with a high growth rate was deposited by ALD, and a thick SnS film was obtained using phase transition of a-SnS2 film by vacuum annealing. Subsequently, we investigated the effect of seed layer on formation of SnS film to verify the applicability of SnS to various devices. Separately deposited crystalline SnS and SnS2 thin films were used as seed layer. The SnS film with a SnS seed showed small grain size and high film density from the low surface energy of the SnS seed. In the case of the SnS film using a SnS2 seed, volume expansion occurred by vertically grown SnS grains due to a lattice mismatch with the SnS2 seed. The obtained SnS film using the SnS2 seed exhibited a large reactive site suitable for ion exchange.

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Section: Introductioncontrasting

confidence: 71%

Development of a SnS Film Process for Energy Device Applications

Choi¹,

Lee

Park³

et al. 2019

Applied Sciences

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“…Halide perovskites and newly emerging systems such as SnS, CuSbS3, and FeS2 may so benefit from these advances to overcome their high-recombination rates and low cell voltages. For example, SnS has a bandgap of 1.1 eV which makes it comparable to Si, yet the champion solar cell efficiency is below 5% and the VOC is only 0.4 V. 218 The minority carrier lifetime of SnS has been recently improved from < 1 ns to > 3 ns by avoiding low concentrations of avoiding extrinsic impurities, 219 which has not solved the problem but illustrates the importance of defect engineering.…”

Section: Enhancing Carrier Lifetimementioning

confidence: 99%

Point defect engineering in thin-film solar cells

et al. 2018

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Control of defect processes in photovoltaic materials is essential for realising high-efficiency solar cells and related optoelectronic devices. The concentrations of native defects and extrinsic dopants tune the Fermi level and enable semiconducting p-n junctions; however, fundamental limits to doping exist in many compounds. Optical transitions involving defect states can enhance photocurrent generation through sub-bandgap absorption; however, such states are often responsible for carrier trapping and non-radiative recombination events that limit open-circuit voltage. Many classes of materialsincluding metal oxides, chalcogenides, and halidesare being examined for next-generation solar energy applications, and each technology faces distinct challenges that could benefit from point defect engineering. We review the evolution in point defect behaviour from Si-based photovoltaics to thin-film CdTe and Cu(In,Ga)Se2 technologies, through to the latest generation halide perovskite (CH3NH3PbI3) and kesterite (Cu2ZnSnS4) devices. We focus on the chemical bonding that underpins the defect chemistry, and the atomistic processes associated with the photophysics of charge carrier generation, trapping, and recombination in solar cells. Finally, we outline general principles to enable defect control in complex semiconducting materials.

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“…The minority‐carrier lifetime has received less attention, yet has historically limited the development of new photovoltaic materials . However, the reported lifetimes of lead‐free alternatives to the perovskites have typically ranged from <0.1 to ≈10 ns . Silver–bismuth double perovskites (e.g., Cs 2 AgBiBr 6 and Cs 2 AgBiCl 6 ) have recently been found to be an exception.…”

Section: Optical Properties Of Cs2agbibr6 and Cs2agbicl6mentioning

confidence: 99%

Fundamental Carrier Lifetime Exceeding 1 µs in Cs₂AgBiBr₆ Double Perovskite

Hoye

Eyre

Wei

et al. 2018

Adv Materials Inter

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185

189

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air-stability of some compositions has motivated researchers to find lead-free alternatives. [7,8] A wide range of materials classes have recently been explored computationally and experimentally. [8,9] In evaluating the potential of these new materials for photovoltaics, much of the focus has been on the bandgap, stability, absorption coefficient, and phase. [8,[10][11][12][13] The minority-carrier lifetime has received less attention, yet has historically limited the development of new photovoltaic materials. [14,15] However, the reported lifetimes of lead-free alternatives to the perovskites have typically ranged from <0.1 to ≈10 ns. [15][16][17] Silver-bismuth double perovskites (e.g., Cs 2 AgBiBr 6 and Cs 2 AgBiCl 6 ) have recently been found to be an exception. Time-resolved photoluminescence (TRPL) measurements of these materials show an initial drop in photo luminescence (PL) over a nanosecond timescale by 0.5-2 orders of magnitude, followed by a slow tail in PL decay. These PL decay traces are fit with a bi-or triexponential model and the longest time constant is attributed to the fundamental lifetime, which has been found to be ≥100 ns. [18][19][20] Given that these materials have also been found to be more stable than methylammonium lead iodide, [18,20] they have attracted significant interest, with many recent investigations of new families of double perovskite compounds with novel properties.There is current interest in finding nontoxic alternatives to lead-halide perovskites for optoelectronic applications. Silver-bismuth double perovskites have recently gained attention, but evaluating their carrier lifetime and recombination mechanisms from photoluminescence measurements is challenging due to their indirect bandgap. In this work, transient absorption spectroscopy is used to directly track the photocarrier population in Cs 2 AgBiBr 6 by measuring the ground state bleach dynamics. A small initial drop is resolved in the ground state bleach on a picosecond timescale, after which the remaining photocarriers decay monoexponentially with a lifetime of 1.4 µs. The majority of the early-time decay is attributed to hot-carrier thermalization from the direct transition to the indirect bandgap, and the 1.4 µs lifetime represents the recombination of most photocarriers. From this lifetime, a steady-state excess carrier density of 2.2 × 10 16 cm −3 under 1 sun is calculated, which is an order of magnitude larger than that for methylammonium lead iodide, suggesting that charge transport and extraction can be efficient in Cs 2 AgBiBr 6 solar cells. Double PerovskiteLead-halide perovskites display remarkable optoelectronic properties, with long diffusion lengths >1 µm, [1,2] strong optical absorption on the order of 10 5 cm −1 , [3] and high photoluminescence quantum efficiencies >80%. [4] These properties have led to rapid increases in the efficiency of perovskite solar cells (up to a certified power conversion efficiency of 22.7%) [5] and light emitting diodes (>11% external quantum efficiency) [6] over a sho...

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Improving the Carrier Lifetime of Tin Sulfide via Prediction and Mitigation of Harmful Point Defects

Cited by 22 publications

References 53 publications

Development of a SnS Film Process for Energy Device Applications

Development of a SnS Film Process for Energy Device Applications

Point defect engineering in thin-film solar cells

Fundamental Carrier Lifetime Exceeding 1 µs in Cs₂AgBiBr₆ Double Perovskite

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Improving the Carrier Lifetime of Tin Sulfide via Prediction and Mitigation of Harmful Point Defects

Cited by 22 publications

References 53 publications

Development of a SnS Film Process for Energy Device Applications

Development of a SnS Film Process for Energy Device Applications

Point defect engineering in thin-film solar cells

Fundamental Carrier Lifetime Exceeding 1 µs in Cs2AgBiBr6 Double Perovskite

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Product

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Fundamental Carrier Lifetime Exceeding 1 µs in Cs₂AgBiBr₆ Double Perovskite