Nonfullerene,
a small molecular electron acceptor, has substantially
improved the power conversion efficiency of organic photovoltaics
(OPVs). However, the large structural freedom of π-conjugated
polymers and molecules makes it difficult to explore with limited
resources. Machine learning, which is based on rapidly growing artificial
intelligence technology, is a high-throughput method to accelerate
the speed of material design and process optimization; however, it
suffers from limitations in terms of prediction accuracy, interpretability,
data collection, and available data (particularly, experimental data).
This recognition motivates the present Perspective, which focuses
on utilizing the experimental data set for ML to efficiently aid OPV
research. This Perspective discusses the trends in ML-OPV publications,
the NFA category, and the effects of data size and explanatory variables
(fingerprints or Mordred descriptors) on the prediction accuracy and
explainability, which broadens the scope of ML and would be useful
for the development of next-generation solar cell materials.