Nonradiative recombination remains a critical barrier to achieving high efficiency in organic solar cells (OSCs), leading to substantial voltage losses that limit performance. To overcome this challenge, we present a molecular engineering strategy based on aggregation-induced emission (AIE) by incorporating tetraphenylethylene (TPE) into fused-ring electron acceptors (FREAs). This modification transforms the traditional A–D1–A architecture into an A–D1–D2 structure, where TPE acts as a steric and electronic modulator to suppress detrimental intermolecular interactions while enhancing radiative recombination.
The designed acceptors—IDIC-TPE and Y6-TPE—exhibit pronounced AIE behavior. In solution, both materials display weak photoluminescence (PL) due to free rotation of the TPE units. Upon aggregation in THF/water mixtures, their PL intensities increase dramatically, especially at water fractions above 50%. For Y6-TPE, the emission intensity reaches 28 times that of the initial solution state, confirming strong AIE characteristics. This enhancement results from restricted intramolecular motion and suppressed π–π stacking in the aggregated phase, which effectively blocks nonradiative decay pathways and promotes radiative recombination.
Electrochemical analysis shows that IDIC-TPE has suitable energy levels—HOMO at −5.47 eV and LUMO at −3.90 eV—making it compatible with common donor polymers like PM6. OSCs based on PM6:IDIC-TPE achieve an open-circuit voltage (Vₒc) of 0.98 V, significantly higher than the 0.78 V observed in PM6:IDIC-4F devices. This improvement is directly linked to reduced nonradiative recombination, as demonstrated by a nearly two-order-of-magnitude increase in external electroluminescent quantum efficiency (EQEEL)—from 8.Ketoconazole Autophagy 8 × 10⁻⁷ to 3.1,4-Dibromo-2,5-diiodobenzene Biological Activity 6 × 10⁻⁵. Consequently, nonradiative voltage loss drops from 0.36 V to 0.26 V.
Ternary blending with PM6:IDIC-4F:IDIC-TPE (1:1.2:0.1, w/w) further enhances device performance, yielding a VOC of 0.83 V and improved power conversion efficiency. Although electron mobility in the PM6:IDIC-TPE blend is moderate (1.32 × 10⁻⁸ cm² V⁻¹ s⁻¹), the suppression of nonradiative processes dominates the overall gain. The results confirm that AIE-active acceptors can effectively mitigate energy losses during charge generation and recombination.PMID:34155814
This study establishes a new paradigm in OSC material design: integrating AIE functionality into high-performance electron acceptors to enable efficient light emission and minimize voltage losses. By leveraging the twisted conformation of TPE, these materials maintain favorable optoelectronic properties while achieving enhanced solid-state luminescence. Future work will explore functionalization of the TPE core with electron-withdrawing groups to fine-tune energy levels without compromising AIE benefits. These findings open a transformative route toward ultra-efficient organic solar cells operating near the Shockley–Queisser limit.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com