A Helical Polycycle Molecular Semiconductor for Durable and Efficient Perovskite Solar Cells

Abstract

Despite the efficiency comparable to crystalline silicon photovoltaics, it is still a severe concern on the long-term stability under the stress of heat, light, and bias potential for perovskite solar cell (PSC).Here, we report a triple aza[6]helicene-based molecular semiconductor (TBTA[6]H) characteristic of a fully fused conjugated backbone. TBTA[6]H presents superior solubility and glass-transition temperature (T g ). An airdoped composite of TBTA[6]H with a high electrical conductivity of 353 μS cm −1 is still featured by a T g of 112 °C, enabling the fabrication of 22% efficiency, 85 °C durable PSCs. The TBTA[6]H composite not only exhibits an excellent morphology stability at 85 °C in PSCs, but also remarkably attenuates the thermal degradation of photoactive perovskite layer. The cell with TBTA[6]H also displays an excellent operation stability under the continuous full sunlight soaking at 55 °C.

Synthesis, Characterization, and Thin-Film Transistor Response of Benzo[i]pentahelicene-3,6-dione

“…A handful of studies are available for other types of devices, such as organic light emitting diodes [ 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 ], organic solar cells [ 57 , 58 , 59 ], and hybrid DSSC [ 60 ] and perovskite solar cells [ 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 ].…”

A Conductive Molecular Semiconductor Composite with Over 160 °C Glass Transition Temperature for Heat‐Resistant Perovskite Solar Cells

“…[14][15][16][17][18][19][20][21][22][23] In this regard, only a few HTLs have been reported to prepare PSCs with long-term thermal stabilities at 85 °C and efficiencies greater than 20%. [24][25][26][27][28][29][30][31] As presented in Figure 1a, for n-i-p typed PSCs with metal oxides as the ETLs, organic HTLs that meet the needs of high-efficiency and thermally stable cells should be born with the following quality factors. First, the highest occupied molecular orbital (HOMO) energy level of an organic HTL should be higher than the valence band edge of perovskite, predictions show that T5H-EP-BMCA possesses a higher HOMO energy level, a higher hole mobility, and a higher T g than T5H-OMeDPA, T5HE-OMeTPA, and spiro-OMeTAD, as presented in Figure 1c-e.…”

“…[ 14–23 ] In this regard, only a few HTLs have been reported to prepare PSCs with long‐term thermal stabilities at 85 °C and efficiencies greater than 20%. [ 24–31 ]…”

Controlling the Decomposition of Hybrid Perovskite by a Dithienopyrrole-Based Hole Transport Layer toward Thermostable Solar Cells

“…However, only a few HTMs are qualified for PSCs with both high efficiency and good 85 °C stability. − In general, most PSCs are not sufficiently resistant to the stresses of bias potential, water moisture, and, in particular, high temperature. − Under the thermal stress of 85 °C, a charge transport layer needs to have a stable morphology and, thus, maintain the functions of efficient charge collection. Even for PSCs using fluorine-doped tin oxide (FTO) glass as the substrate and oxide semiconductor as the ETL, the HTL should also serve as an effective barrier for the entry of moisture and the release of volatile components.…”

“…It can be concluded that the higher HOMO energy level and the smaller reorganization energy jointly result in the faster hole injection for H2, in terms of the semiclassical Marcus electron transfer theory. As shown in Figure S5, owing to a higher HOMO energy level, H2 exhibits a faster hole injection than spiro, DOP-OMeDPA, and TBTA[6]­H . Moreover, the insertion of a PbI 2 /MF interlayer can bring forth an increase in τ hi .…”