Engineering Solar Cell Absorbers by Exploring the Band Alignment and Defect Disparity: The Case of Cu‐ and Ag‐Based Kesterite Compounds

Yuan, Zhen Kun; Chen, Shiyou; Xiang, Hongjun; Gong, Xin; Walsh, Aron; Park, Ji-Sang; Repins, Ingrid; Wei, Su‐Huai

doi:10.1002/adfm.201502272

Cited by 308 publications

(402 citation statements)

References 98 publications

(101 reference statements)

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“…Based on the similar oxidation states of Cu and Ag, we propose to tackle the aforementioned problems by alloying CTS with Ag (ACTS). Alloying chalcopyrite materials with Ag has been shown to have several advantageous properties for kesterite and Cu(In,Ga)S 2 (CIGS) absorbers [19]- [26] [(Ag, Cu) 2 ZnSnS 4 (ACZTS) and (Ag,Cu)(In,Ga)S 2 (ACIGS)]. Ag replaces Cu in these materials, which increases the band gap [19], [23], [24], [26], decreases the p-type doping [23], as well as reduces intragrain defects and defect states [19]- [21], [23], [26].…”

Section: Introductionmentioning

confidence: 99%

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Silver-Doped Cu₂SnS₃Absorber Layers for Solar Cells Application

Wild

Babbe

Robert

et al. 2018

IEEE J. Photovoltaics

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Abstract-The p-type semiconductor Cu 2 SnS 3 is alloyed with Ag to investigate its effect on absorber layer and solar cell properties. Ag replaces the Cu in (Cu 1-x Ag x ) 2 SnS 3 (ACTS) up to x ࣘ 6% at 550°C. Above this percentage, Ag forms secondary phases. We find a significant increase in grain size, from hundreds of nanometers to several microns, and increased photoluminescence yield with increasing Ag concentration. Low-temperature photoluminescence measurements show that compensation is increased for the ACTS absorber layers, which could be beneficial for CTS, but also that the electrostatic band gap fluctuations are increased. The external quantum efficiency of the solar cells made from ACTS shows an increased carrier collection length from 320 nm for CTS to 700 nm and a thicker buffer layer. We attribute the increase in collection length to both increased depletion width (increased compensation) and diffusion length (

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Section: Introductionmentioning

confidence: 99%

“…First, the band gap of CTS is around 0.93 eV [1]- [5], which is lower than desired for single-junction solar cells. Second, a decrease of p-type doping when alloying with Ag is expected since the formation energy of Ag donor defects is lower than for acceptors for Ag 2 ZnSnS 4 (AZTS) [19], and Ag may occupy Cu vacancies Fig. 1.…”

Section: Introductionmentioning

confidence: 99%

Silver-Doped Cu₂SnS₃Absorber Layers for Solar Cells Application

Wild

Babbe

Robert

et al. 2018

IEEE J. Photovoltaics

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“…Insufficient buffer coverage can also lead to decreased VOC 58 . The position of Fermi level close to the middle of hetero-interface due to Fermi level pinning 52 , the absence of charge inversion at hetero-interface 13,59 , the high density of interface defects 59 and the presence of secondary phases at the interface 61,62 are mentioned as well to explain the VOC deficit compared to CIGSSe solar cells. Concerning pure sulfide CZTS absorber, it has been demonstrated that bandgap narrowing at the front interface reduces VOC 60 .…”

Section: Mapping Of Fundamental Failures In Cd-free Kesterite Solar Cmentioning

confidence: 99%

“…Shockley-Read-Hall (SRH) recombination on point defects in the bulk of the absorber is generally said to be responsible for this short lifetime 42 but the influence of band tails, grain boundaries or even interfaces on lifetime is rarely discussed 13 . SRH recombination and tunneling-enhanced recombination 38 , grain boundary recombination 43 , low carrier mobility due to defect scattering 46 or carrier localization 50 and insufficient quasi-Fermi level splitting because of too low carrier density 51 or Fermi level pinning 52 are mentioned as well as responsible for this VOC deficit. Moreover, the absence of internal electric field cannot counterbalance these poor electronic properties 43 .…”

Section: Mapping Of Fundamental Failures In Cd-free Kesterite Solar Cmentioning

confidence: 99%

Analysis of Failure Modes in Kesterite Solar Cells

Grenet

Suzon

Emieux

et al. 2018

ACS Appl. Energy Mater.

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An intense research activity has been carried out in the past few years to improve efficiencies and understand limitations in kesterite based solar cells. Despite notable efforts to determine and list the different failure modes affecting the photovoltaic properties of these devices, very few works try to quantify and classify the effect of these failure modes. In this study, an exhaustive literature review has first been conducted to determine the different causes leading to limited efficiencies in kesterite devices with an additional focus on cadmium free and critical raw material free devices. Second, an original approach has been employed to quantify the impact of these failure modes on solar cells with the evaluation of feedbacks from 18 scientific experts working on kesterite technology. The result of this survey is analyzed, which allow to determine what should be the research priority for the community to improve efficiencies and drive kesterite technology to the market.

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“…As a result, current density falls significantly with the higher thickness of CZTS (Figure 2(a)) because of the reduced optical power absorption in the bottom cell. Thus, higher thickness of [19] 7 [18] 8.5 [17] 7 [16] Band gap (eV) 1.9 [14] 1.45 [18] 0.97 [17] 0.9 [16] Electron affinity (eV) 3.6 [19] 4.1 [24] 4.05 [17,25] 4.05 [13] Electron effective mass (m e /m o ) 0.37 [14,15] 0.18 [13,16] 0.08 [17] 0.07 [13,16] Hole effective mass (m p /m o ) 1.68 [14] 2 [13,16] 0.3 [17] 0.2 [13,16] Electron mobility (cm 2 V À1 s À1 ) 3 0 [26] 40 [21,24] 75 [23] 145 [13,21] Hole mobility (cm 2 V À1 s À1 ) 1 0 [27] 25 [21] 1 [17,23] 35 [13,21] Acceptor concentration (cm…”

mentioning

confidence: 99%