Photoconductive noise microscopy revealing quantitative effect of localized electronic traps on the perovskite-based solar cell performance

Cho, Duckhyung; Hwang, Taehyun; Cho, Dong-guk; Park, Byungwoo; Hong, Seunghun

doi:10.1016/j.nanoen.2017.11.009

Cited by 18 publications

(28 citation statements)

References 48 publications

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“…Also, the nanoscopic origins such as point defects and consequent electronic traps are regarded as critical elements on the optoelectronic properties, and, therefore, distinctive deposition routes of perovskite cause a considerable difference in the photovoltaic performance. [3][4][5][6] The postdeposition treatment of the perovskite film is generally utilized to improve the solar cell performance. 7,8 The effects of CH 3 NH 3 Cl (MACl) post-treatment are widely investigated in the aspect of surface properties and perovskite reconstruction, and its values are successfully demonstrated in the state-of-the-art devices.…”

Section: Introductionmentioning

confidence: 99%

Methylammonium-chloride post-treatment on perovskite surface and its correlation to photovoltaic performance in the aspect of electronic traps

Hwang

Yun

Lee

et al. 2019

Journal of Applied Physics

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Herein, MACl post-treatment is utilized for MAPbI 3 and (Cs 0.05 FA 0.79 MA 0.16)Pb(I 0.84 Br 0.16) 3 (MA, methylammonium; FA, formamidinium). Photoluminescence of both perovskite films exhibits a peak shift to the higher emission energy as well as a slower decay of recombination by the MACl treatment, suggesting the passivation of defects in band tail states. Photovoltaic performance is further correlated with the change of deep electronic traps in the bandgap, which is characterized through capacitance analyses of solar cells. Degradation of MAPbI 3 cells by the MACl treatment is attributed to the additional deep-trap formation, and the improvement of photovoltaic parameters for triple-cation perovskites is correlated with the reduction of deep traps with trap-level shifts toward the band edge. The reactive characters of MAPbI 3 against post-treatment conditions seem to be responsible for the deep-trap formation as evidenced by the microstructural/morphological results, and consequently, the improved resistance to trap the formation of triple-cation perovskites provides viability for further performance enhancement by surface passivation.

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Section: Introductionmentioning

confidence: 99%

Methylammonium-chloride post-treatment on perovskite surface and its correlation to photovoltaic performance in the aspect of electronic traps

Hwang

Yun

Lee

et al. 2019

Journal of Applied Physics

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“…In this case, we can assume that each noise source traps and releases charge carriers independently with different relaxation times, and use a previously reported simulation method to obtain the map of the localized charge trap density N eff from the measured normalized PSD map (Figure 4g). [ 14,19,26 ] In the method, a differential analysis based on the Wiener–Khintchine theorem shows that the N eff in the small segment of a 2D film in the area of Δ x Δ y can be written as

N_{eff} (f, x, y) = \frac{{(Δ c)}^{2}}{I^{2}} \frac{f}{k T} \times \frac{Δ S_{I} (f, x, y)}{Δ x Δ y}

where the I, f , Δ C , and Δ S I are a current in the film segment, a frequency, a charge carrier number in the film segment, and a current noise PSD generated by the film segment, respectively. For the calculation, we used the Δ x Δ y value of ≈100 nm 2 which is the effective contact area of our conducting AFM probe provided by the manufacturer.…”

Section: Resultsmentioning

confidence: 99%

“…Electrical noises in a conducting channel can be generated by various noise sources. [26,33] In the case of sSWCNTs and metallic thin films on the SiO 2 substrate, localized charge traps in the underlying SiO 2 are reported as a major source of electrical noises. In this case, we can assume that each noise source traps and releases charge carriers independently with different relaxation times, and use a previously reported simulation method to obtain the map of the localized charge trap density N eff from the measured normalized PSD map (Figure 4g).…”

Section: Wwwadvelectronicmatdementioning

confidence: 99%

“…[10] For more quantitative analysis about the effect of sSWCNTs, we calculated a resistivity map from the current map using the iterative simulation method as reported previously (Figure 4d). [14,19,26] In the resistivity map, the regions with embedded sSWCNTs (yellow lines) can be easily identified as a low resistivity region, and they correspond to high current regions in the current map. The averaged resistivity of pure Au regions (blue regions) without sSWCNTs was 1.58 × 10 −5 Ω cm, which was similar to the previously reported resistivity of Au thin films.…”

Section: Introductionmentioning

confidence: 99%

“…In this case, we can assume that each noise source traps and releases charge carriers independently with different relaxation times, and use a previously reported simulation method to obtain the map of the localized charge trap density N eff from the measured normalized PSD map (Figure 4g). [14,19,26] In the method, a differential analysis based on the Wiener-Khintchine theorem shows that the N eff in the small segment of a 2D film in the area of ΔxΔy can be written as ( ,…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Semiconducting Carbon Nanotubes Embedded in a Metallic Film for a Thermistor Device with an Adjustable Temperature Coefficient and Reduced Noise Source Activities

Shin

Cho

Kim

et al. 2020

Adv Elect Materials

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On the other hand, a key issue in using sSWCNT channels for device applications (i.e., a transistor, temperature sensors) can be the interface between sSWCNTs and metal electrodes. [10] Previous reports show that the formation of Schottky barriers between sSWCNT and metal electrodes may increase the contact resistance and often electrical noises, resulting in the degradation of overall device performances. [11,12] However, the effect of sSWCNTs on the nanoscale transport properties (i.e., conductivity, charge trap activities) of the metal-sSWCNT interface structures has not been clearly understood yet. Herein, we report semiconducting SWCNTs embedded in Au films for a thermistor device with an adjustable temperature coefficient and reduced noise source activities. In this work, an Au thin film was deposited on sSWCNT network layers to build a thermistor device. Then, a scanning noise microscopy (SNM) method was utilized to map the resistivity and noise source activities on the hybrid film with a nanoscale resolution. The sSWCNT/ Au hybrid thin films showed a linear temperature-resistance dependence with minimal hysteresis. Interestingly, sSWCNTmetal hybrid films with rather thin Au films exhibited a negative temperature coefficient of resistance (TCR) values, while those with rather thick Au films showed a positive TCR. It indicates we can control the TCR values simply by changing the Au film thickness. The resistivity map measured by the SNM method exhibited three times smaller resistivity on the Au films with sSWCNTs, showing that sSWCNTs can work as a high conductance current path and enhance the conductivity of the film. Furthermore, we observed the 18 times smaller noise source activities in the region with sSWCNTs. These results show that sSWCNTs in thin metallic films can enhance the conductivity and reduce electrical noises, enabling high-performance device applications such as thermistors.

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Minimizing the transport loss and degradation of perovskite optoelectronics via grain dimerization technique

Kim

Yun

Park

et al. 2022

EcoMat

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As a next‐generation photovoltaic device, perovskite solar cell (PSC) is rapidly emerging by its appealing properties. Nevertheless, owing to the degradation which is initiated from the grain boundaries and dangling bonds on the surface, PSC is struggling with not only power conversion efficiency (PCE) but its stability. Herein, dimerization technique using diphenyl(4‐vinylphenyl)phosphine (DVP) is suggested to heal both bulk and interfaces of the perovskite grains. Effective DVP dimerization results in the minimized‐defect perovskite and constructs strong cross‐linking networks inside the grains, enabling improved device performance, reproducibility and stability. Furthermore, hydrophobic species of DVP boost the stability against humidity, which is confirmed by the solar cell dipped in water. As a result, this work obtained PSCs with improved film morphology, reproducibility and stability by DVP dimerization, achieving 21.1% of PCE stable for 1000 h under extreme conditions (AM 1.5G and 60°C, encapsulated).

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Photoconductive noise microscopy revealing quantitative effect of localized electronic traps on the perovskite-based solar cell performance

Cited by 18 publications

References 48 publications

Methylammonium-chloride post-treatment on perovskite surface and its correlation to photovoltaic performance in the aspect of electronic traps

Methylammonium-chloride post-treatment on perovskite surface and its correlation to photovoltaic performance in the aspect of electronic traps

Semiconducting Carbon Nanotubes Embedded in a Metallic Film for a Thermistor Device with an Adjustable Temperature Coefficient and Reduced Noise Source Activities

Minimizing the transport loss and degradation of perovskite optoelectronics via grain dimerization technique

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