Semitransparent Organic Solar Cells with Efficiency Surpassing 15%

Abstract

counterparts and is very attractive for developing semitransparent organic solar cells (ST-OSCs), which have great potential application in building integrated photovoltaic, agricultural greenhouse, car window, and so on. [5,6] Different from opaque device that is concerned mostly with power conversion efficiency (PCE), ST-OSCs also value the transparency in the visible region and adopt average visible transmittance (AVT) to assess their see-through function. [7] However, there is a trade-off relationship between the see-through function and photovoltaic performances since enhancing the light transmission generally leads to lower amount of photons to be utilized. Therefore, efforts including material designing and device engineering are widely employed to reconcile the intrinsic contradiction between AVT and PCE. [8][9][10][11][12][13][14][15][16] Ideally, the photon-absorbing materials in ST-OSCs should have the main absorption in the NIR region and weak absorption in the visible region. [17] Previously, various narrow bandgap polymer donors were synthesized and matched with fullerene acceptors in ST-OSCs. [18,19] Recently, with the aid of advances in materials designing of NIR-absorbing non-fullerene electron acceptors, the PCEs of ST-OSCs have already surpassed 14%. [20,21] Meanwhile, optical engineering technologies, including photonic crystals, [22,23] antireflective device structures, [24,25] or optical microcavity structures, [26,27] have been applied to improve the PCEs and optimize the transmission spectra with deliberately designed layout but energy-consuming process. Other strategies, including multi-component, [28,29] sequentially deposited active layer [30,31] and thickness optimization [20] are also implemented to regulate photon harvesting range and improve PCEs in these fields.More directly, lowering the large-bandgap donor content in bulk-heterojunction (BHJ) has been demonstrated as a facile strategy to tune the transmittance spectrum of active layer. [32][33][34] The AVTs of D18-Cl:Y6-1O films have been continuously changed from 30.3% to 68.0% through ranging the donor and acceptor weight ratio (D:A ratio) from 1.1:1.6 to 0.1:1.6. [4] These previous works imply the feasibility of achieving high AVT from low-donor content ST-OSCs. Nevertheless, the performance optimization of OSCs with dilute donors still remains a challenge, mainly originating from the imbalanced charge Semitransparent organic solar cells (ST-OSCs) have promising prospects for building or vehicle integrated solar energy harvesting with energy generation and see-through function. How to achieve both an adequate average visible transmittance (AVT) and high-power conversion efficiency (PCE) is always the key issue. Herein, a simple but effective strategy for constructing high performance ST-OSCs by introducing a small molecule [2-(9-H-Carbazol-9-yl) ethyl] phosphonic acid (2PACz) into a low-donor content active layer is reported. The fill factor is improved from 70.5% to 75.5% and correlated to the mitigated charge recombination a...

Random copolymerization strategy for non-halogenated solvent-processed all-polymer solar cells with a high efficiency of over 17%

“…To further illustrate the impact of introducing the BDD unit on charge recombination, transient photovoltage (TPV) measurements were conducted. 65 As shown in Fig. S23 (ESI†), the TPV decay dynamics of the blend films can be used to extract the carrier lifetimes ( τ ) under open-circuit conditions.…”

“…To carry out more comprehensive analysis, in addition to τ values, the corresponding carrier densities ( n ) can also be estimated using charge-extraction (CE) measurements performed at various illumination intensities in parallel. 65 Fig. S23 (ESI†) delineates that the n values vary with the light intensity, and the relationship between τ and n is depicted in Fig.…”

Recent Advances in Single‐Junction Organic Solar Cells

“…The utilization of solar photons in the NIR region has become increasingly important. [83] Using the low-band gap NFA IEICO-4Cl, we fabricated efficient semi-transparent OSCs with controllable colors (Figure 7a). [21] Yip et al [84] demonstrated that a heat-insulation function could be effectively integrated into semitransparent OSCs (Figure 7b).…”

“…Semitransparent photovoltaic cells should have high transmittance in the visible light range. The utilization of solar photons in the NIR region has become increasingly important [83] …”

A meta-alkylthio-phenyl chain–substituted small-molecule donor as the third component for high-efficiency organic solar cells

“…Bulk heterojunction (BHJ) OSCs have attracted tremendous attention due to their various advantages, such as mechanical exibility, solution-processed capacity, light weight, and semitransparency. [1][2][3][4][5][6] In recent years, OSCs have undergone rapid progress due to the emergence of non-fullerene acceptors, e.g., ITIC, 7 IT-4F, 8 O-IDTBR, 9 PTIC, 10 and Y6. 11,12 Single-junction binary OSCs with Y6 and its derivatives as acceptors afford high PCEs of over 17%.…”