Temperature and Spectral Effects on Perovskite Solar Cells: A SCAPS-1D Simulation Study

The rapid advancement of photovoltaic (PV) technology has positioned perovskite solar cells (PSCs) as the foremost next-generation solar energy conversion devices. This is due to its ease of fabrication and high power conversion efficiency (PCE) [1].

Perovskite solar cells (PSCs), identified in the early 2010s, exhibit variable bandgap properties alongside enhanced optoelectronic performance, attaining efficiencies similar to conventional silicon solar cells [2, 3]. The temperature (T) and the incoming light spectrum (λ) significantly influence the performance and longevity of PSC devices. Further investigation is necessary to enhance our understanding of them, which will facilitate improved sales and development. The performance of perovskite solar cells (PSCs) across various spectra is influenced by their morphology and bandgap (Eg). This describes the process by which various wavelengths of light can be converted into electricity. The bandgap (Eg) of perovskite materials typically ranges from 1.1 eV to 2.3 eV and makes available the spectral match with the solar spectrum of the emitted light, allowing for an implementation in a tandem cell configuration [4, 5]. The spectrum of sunlight, which varies based on geographic location and weather conditions, directly influences the operational efficiency and overall performance of the device. The external quantum efficiency (EQE) spectrum is a critical method for analyzing the variation of response with wavelength.

The fundamental photovoltaic process in perovskite solar cells (PSCs) entails the separation and movement of electron-hole pairs (e--h+), resulting in the generation of current. The Shockley-Queisser (SQ) limit, which is the theoretical maximum efficiency threshold of 34.9% for concentrated sunlight and 32.6% for non-concentrated sunlight, is contingent upon the solar spectrum and the band-gap (Eg) [6, 7]. For an optimal device under 1.5G light (1000 W/m²), the greatest theoretical efficiency (η_max) can be expressed as:

$\eta_{\max }=\frac{q \times V_{o c} \times J_{s c} \times F F}{P_{i n}}$ 

where,

$q$: elementary charge ($1.602 \times 10^{-19}$ C)

$V_{o c}$: Open-circuit voltage (depends on bandgap (Eg))

$J_{s c}$: Short-circuit current density (depends on (Eg))

FF: Fill factor (depends on (V_oc))

$P_{i n}$: Incident solar power density

$\eta_{\max (E g)} \approx E_g^2 \cdot e^{\frac{-E_g}{E_0}}$

where,

E₀ ≈ 0.9 eV

This expression reflects the trade-off between increasing voltage (V_oc) (with higher Eg) and decreasing current $J_{s c}$ (fewer photons absorbed). The optimum bandgap for maximum efficiency is ≈1.34 eV, yielding η_max ≈ 33.7% [8].

The temperature dependence of (V_oc) is given by:

$V_{o c}(T)=\frac{k B T}{q} \ln \left(\frac{J_{s c}}{J_o(T)}+1\right)$

where,

$k B$: Boltzmann constant (1.38×10⁻²³ j/k).

$T$: Absolute temperature (k).

$J_{s c}$: Short-circuit current density (weakly dependent on t).

$J_o$(T): Temperature-dependent reverse saturation current density [9-11].

Recent advances in bandgap engineering and spectral tuning have enhanced the efficiency and thermal stability of PSCs. Techniques such as compositional texture engineering minimize phase segregation, enabling stable wide-bandgap perovskites with PCEs > 20% and the superior operational lifetimes under thermal stress [12-14]. Meanwhile, advancements in manufacturing processes such as gas-quenched crystal growth have also improved crystal quality and lower defect densities, thus lessening performance losses from temperature (T) and spectral variation ($\lambda$) [15]. This study investigates the coupled effects of temperature (T) and spectrum ($\lambda$) on PSCs performance using SCAPS-1D simulation, of analyzing their impact on fill factor (FF) and efficiency (η).

3.1 Current-voltage (I-V) characteristics and temperature influence

The simulated current-voltage (I-V) characteristics of the FTO/CdS/CH₃NH₃PbI₃/CuO perovskite solar cell under illumination wavelengths of 400 nm, 450 nm, and 500 nm were examined across a temperature range of 290 K to 340 K, as depicted in Figure 2(a-f). The open-circuit voltage (V_oc) significantly declines with rising temperature, especially under illumination at 400 nm. The decline is mainly due to the rise in reverse saturation current density (J_o), aligning with the diode equation Ln [29].

$V_{O C}=\frac{n k T}{q} \operatorname{Ln}\left(\frac{J_{s c}}{J_{\mathrm{o}}}+1\right)$

2a.png

(a) current-voltage characteristics at T = 290 K

2b.png

(b) current-voltage characteristics at T = 300 K

2c.png

(c) current-voltage characteristics at T = 310 K

2d.png

(d) current-voltage characteristics at T = 320 K

2e.png

(e) current-voltage characteristics at T = 330 K

2f.png

(f) current-voltage characteristics at T = 340 K

Figure 2. Simulated current-voltage (I-V) characteristics of the FTO/CdS/CH₃NH₃PbI₃/CuO perovskite solar cell under 400 nm, 450 nm, and 500 nm illumination across temperatures ranging from 290 K to 340 K

Such thermal behavior reflects enhanced recombination near the absorber interface, especially for shorter wavelengths with shallow absorption depth [30]. Among all conditions, 450 nm illumination yielded the highest V_oc and J_sc, indicating more favorable spectral absorption and charge transport properties [31]. Furthermore, distortion of the I-V curve at elevated temperatures (330-340 K) under 400 nm suggests increased series resistance or interface instability, possibly caused by degradation at the perovskite/transport layer interfaces [32, 33].

3.2 Open-circuit voltage (V_OC) characteristics and temperature influence

The simulated open-circuit voltage (V_oc) of the FTO/CdS/CH₃NH₃PbI₃/CuO perovskite solar cell under illumination wavelengths of 400 nm, 450 nm, and 500 nm was analyzed across temperatures ranging from 290 K to 340 K (Figure 3). V_oc exhibits a clear decrease with increasing temperature (Table 2). At 290 K, the maximum (V_oc) values were approximately 0.96 V, 0.82 V, and 0.82 V for 400 nm, 450 nm, and 500 nm, respectively. By 340 K, V_oc dropped by nearly 20%, consistent with the exponential rise in reverse saturation current density (J_o), explained by the Shockley diode equation [34-36]. The thermal activation of trap-assisted recombination increases with temperature, leading to degradation of V_oc.

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Figure 3. Open-circuit voltage (V_oc) characteristics and temperature influence

Notably, the degradation at 400 nm illumination is more significant due to carriers generated near the surface, prone to higher recombination losses because of shallower penetration depth [37]. Such thermal degradation is mainly and universally caused by an exponential increment of reverse saturation current density (J_o) of a diode with temperature, by evaluating the Shockley diode equation in a wide temperature range.

$V_{O C}=\frac{n k T}{q} \operatorname{Ln}\left(\frac{J_{s c}}{J_0}+1\right)$

Table 2. Open-circuit voltage (V_oc) at various temperatures and illumination wavelengths

3.3 Short-circuit current density (J_SC) characteristics and temperature influence

The short-circuit current density (J_sc) increased slightly with temperature across all wavelengths (Table 3, Figure 4), attributed to enhanced carrier mobility and reduced non-radiative recombination at higher temperatures [37, 38]. The lowest increase occurred at 400 nm, linked to increased surface recombination due to shallower light penetration [37, 39].

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Figure 4. The relationship between short-circuit current density (J_sc) and temperature (T)

Table 3. Short-circuit current density (J_sc) at different temperatures and illumination wavelengths

Carrier lifetime calculations are typically conducted for minority carriers. Consequently, the carrier lifetime is designated as the minority carrier lifetime. A reduced minority carrier lifetime indicates an increased recombination rate of excess carriers within the semiconductor.

3.4 Fill factor (FF %) as a function of temperature and wavelength

The FF % dependence versus temperature was studied under illumination at 400 nm, 450 nm, and 500 nm. The obtained results are organized in Table 4 and Figure 5, which unveils a nonlinear dependence where FF % increases with temperature until a maximum is achieved at peaking near 300 K and 310 K (~85%), then decreases with continued heating. This suggests the presence of an optimal thermal window that maximizes charge extraction and minimizes resistance and recombination losses.

Table 4. Fill factor (FF %) values at various temperatures and wavelengths

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Figure 5. The relationship between fill factor (FF) and temperature (T)

At 290 K, FF % at 400 nm (72.22%) was further reduced compared with 450 nm (84.87%) and 500 nm (84.91%) due to more significant surface recombination at shorter wavelengths with a shallow optical penetration depth [34]. FF % was also enhanced with temperature and reached the maximum value of ~84.93% at 310 K for all wavelengths, which is due to the increased carrier mobility and decrease in the series resistance [35].

For temperatures above 310K, FF % decreased somewhat to (83.46 % – 83.50%) at 340K, which is attributed to higher ion migration, deterioration of the interface, and non-radiative recombination processes [36].

3.5 Temperature dependence of power conversion efficiency (PCE)

The power conversion efficiency (PCE) of the solar cell was evaluated across a temperature range from 290 K to 340 K under three illumination wavelengths (400 nm, 450 nm, and 500 nm). As shown in Figure 6 and summarized in Table 5, PCE decreases consistently with increasing temperature for all wavelengths.

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Figure 6. The relationship between power conversion efficiency (PCE) and temperature (T)

Table 5. Power conversion efficiency (PCE) values at various temperatures and illumination wavelengths

Specifically, PCE declines by approximately 8–9% when the temperature rises from 290 K to 340 K, reflecting the detrimental effect of thermal stress on device performance [34, 39].

Of the wavelengths examined, 450 nm illumination yields the highest efficiency, reaching 25.15% at 290 K. This phenomenon is due to the beneficial overlap between the photon energy at this wavelength and the absorption spectrum of the perovskite active layer. This results in optimal charge carrier generation and minimal recombination losses, thereby enhancing photovoltaic performance [37, 40].

Conversely, 400 nm light exhibits the lowest power conversion efficiency values despite possessing higher photon energy. This occurs primarily because shorter-wavelength photons exhibit limited penetration depth, resulting in the generation of charge carriers near the surface, where surface recombination and defect-induced trapping are more pronounced. This reduces the effective carrier collection efficiency [41]. The performance at 500 nm lies between that of the other two wavelengths. Photons at 500 nm exhibit greater penetration into the absorber layer, facilitating the generation of bulk carriers. Nonetheless, due to their lower energy compared to 450 nm photons, the PCE is marginally reduced [41].

The reduction in PCE with increasing temperature is fundamentally associated with enhanced trap-assisted recombination caused by thermal energy, which reduces the open-circuit voltage (V_oc) and fill factor (FF) [35, 38]. Increased reverse saturation current density (J_o) leading to higher recombination rates [34]. Thermal effects cause variations in series resistance (Rs) and shunt resistance (RSh), increasing resistive losses and further degrading efficiency [42].

Overall, these findings highlight the critical influence of both spectral illumination and temperature on perovskite solar cell performance. Engineering the device to optimize spectral response and improve thermal stability is essential for enhancing real-world operational efficiency [43, 44].

3.6 Temperature and light spectrum range effect on carrier lifetime and resistances

The lifetime of the minority carrier has a big effect on the recombination rates and the overall efficiency of perovskite solar cells. This study did not directly assess carrier lifetime; however, its effects were integrated into the SCAPS-1D simulation via recombination parameters aligned with experimental literature [44, 45]. Longer carrier lifetimes are linked to lower recombination losses, which improve the short-circuit current density (J_sc) and fill factor (FF) [46]. The observed decrease in fill factor (FF) and alteration of the current-voltage (I-V) characteristics at elevated temperatures signify an increase in series resistance (Rs) and shunt resistance (RSh). The resistances are mainly caused by interface degradation, ion migration, and defect formation due to heat, which speed up recombination and slow down charge transport [44, 47]. Resistive losses increase as the series resistance (Rs) goes up. This lowers the fill factor and the power conversion efficiency (PCE) when the temperature rises.