Determination and interpretation of the optical constants for solar cell materials

Fujiwara, Hiroyuki; Fujimoto, Sanji; Tamakoshi, Masato; Kato, Masato; Kadowaki, Hideyuki; Miyadera, Tetsuhiko; Tampo, Hitoshi; Chikamatsu, Masayuki; Shibata, Hajime

doi:10.1016/j.apsusc.2016.09.113

Cited by 27 publications

(27 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Front TCO absorption Considered Neglected [25], this controversy is found to originate from the effect of rough surface [33] and quite consistent optical characterization has been made to minimize the roughness effect in the result of Fig. 4.…”

Section: Shadow Loss 5% Neglectedmentioning

confidence: 99%

Maximum Efficiencies and Performance-Limiting Factors of Inorganic and Hybrid Perovskite Solar Cells

et al. 2019

Self Cite

View full text Add to dashboard Cite

The Shockley and Queisser limit, a well-known efficiency limit for a solar cell, is based on unrealistic physical assumptions and its maximum limit is seriously overestimated.To understand the power loss mechanisms of record-efficiency cells, a more rigorous approach is necessary. Here, we have established a formalism that can accurately predict absolute performance limits of solar cells in conventional thin film form. In particular, a formulation for a strict evaluation of the saturation current in a nonblackbody solar cell has been developed by taking incident angle, light polarization and texture effects into account. Based on the established method, we have estimated the maximum efficiencies of 13 well-studied solar cell materials [GaAs, InP, CdTe, a-HC(NH 2 ) 2 PbI 3 ] in a 1-µm-thick physical limit. Our calculation shows that over 30% efficiencies can be achieved for absorber layers with sharp absorption edges (GaAs, InP, CdTe, CuInGaSe 2 , Cu 2 ZnGeSe 4 ). Nevertheless, many record-efficiency polycrystalline solar cells, including hybrid perovskites, are limited by open-circuit voltage and fill-factor losses. We show that the maximum conversion efficiencies described here present alternative limits that can predict the power generation of real-world solar cells. *fujiwara@gifu-u.ac.jp sc J kT qV J J −  

show abstract

Section: Shadow Loss 5% Neglectedmentioning

confidence: 99%

Maximum Efficiencies and Performance-Limiting Factors of Inorganic and Hybrid Perovskite Solar Cells

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…Furthermore, some of the α spectra show relatively large α values in the energy region even below E g . Rather surprisingly, the large variation of α observed in Figure a is artifact and originates from the large surface roughness of MAPbI 3 samples …”

Section: Light Absorption In Mapbi3mentioning

confidence: 79%

“…In such cases, strong light scattering occurs and roughness modeling becomes quite difficult. When the ellipsometry analysis is performed for such samples, the extracted optical data generally show strong artifacts, such as non‐zero α values in the energy region below E g …”

Section: Light Absorption In Mapbi3mentioning

confidence: 99%

Optical Characteristics and Operational Principles of Hybrid Perovskite Solar Cells

Fujiwara

Kato

Tamakoshi

et al. 2018

Physica Status Solidi (a)

Self Cite

View full text Add to dashboard Cite

In this article, the optical properties of various APbX 3 -type hybrid perovskites (A: center cation; X: halogen atom) and operational principles of hybrid perovskite solar cells are reviewed and discussed. In particular, controversy observed for the absorption coefficient (α) of CH 3 NH 3 PbI 3 is found to originate from large surface roughness of the solution-processed perovskite layers. The comparison of the accurate experimental α with the theoretical results indicates clearly that the hybrid perovskite has a direct band gap with negligible indirect nature. Moreover, the A-site cation plays a critical role in determining the absorption strength of hybrid perovskites through hydrogen bonding interaction. In contrast to general understanding that hybrid perovskite solar cells operate in p-i-n type solar cells, a simple p-n junction formation explains the observed solar cell characteristics well. The high short-circuit current observed in the solar cells is further interpreted by the suppressed parasitic light absorption and efficient optical confinement in the solar cells, rather than the high α of hybrid perovskite materials. This article provides renewed principles for the optical processes and operation of hybrid perovskite solar cells.

show abstract

“…Non-excitonic nature of MAPbI3 has already been confirmed and discussed quite extensively [47,71,72]. [26,27,77]. By applying the self-consistent GW (scGW) approximation, the optical transition analyses of MAPbX3 have been performed and slightly different assignments have been proposed for MAPbI3 [52].…”

Section: Optical Transitions In Hybrid Perovskitesmentioning

confidence: 92%

“…11 shows the optical transition analysis performed for MAPbI3[77]. In this analysis, the energy separation between the conduction and valence bands (EC -EV) is calculated first for each interband transition of Vj → Ck.…”

mentioning

confidence: 99%

Organic-Inorganic Hybrid Perovskite Solar Cells

Fujiwara

Podraza

Alonso

et al. 2018

Spectroscopic Ellipsometry for Photovoltaics

Self Cite

View full text Add to dashboard Cite

Quite high efficiencies exceeding 20% have been realized in solar cells incorporating organic-inorganic hybrid perovskites (APbX3), which have a unique structure with a center cation [A = CH3NH3 + , HC(NH2)2 + ] located within a PbX3  cage (X = I, Br, Cl). Superior characteristics of hybrid perovskite solar cells can be understood from the nature of optical transitions and the efficient carrier collection in the device. From these points of view, this chapter provides details on optical properties of various hybrid perovskite materials and carrier dynamics in the solar cells. In particular, based on the first-principles analyses of different perovskite materials, we present universal rules that allow the unified interpretation of the optical absorption phenomenon in APbX3 perovskites. The external quantum efficiency (EQE) analysis further reveals that high short-circuit current densities (>20 mA/cm 2) observed in the perovskite solar cells originate from electric-field-assisted carrier collection and the suppressed optical losses in the devices. Although hybrid perovskites have quite favorable characteristics for solar cells, these materials exhibit rather intense phase change upon exposure to humid air. In this chapter, the degradation process of CH3NH3PbI3 in humid air, characterized by applying ellipsometry technique, is further presented and discussed.

show abstract

Determination and interpretation of the optical constants for solar cell materials

Cited by 27 publications

References 38 publications

Maximum Efficiencies and Performance-Limiting Factors of Inorganic and Hybrid Perovskite Solar Cells

Maximum Efficiencies and Performance-Limiting Factors of Inorganic and Hybrid Perovskite Solar Cells

Optical Characteristics and Operational Principles of Hybrid Perovskite Solar Cells

Organic-Inorganic Hybrid Perovskite Solar Cells

Contact Info

Product

Resources

About