The Dilemma of Standardizing Indoor Photovoltaic Characterisation: Embracing Diversity for Powering the IoT

In this viewpoint contribution, we argue that the emerging landscape of indoor photovoltaics poses unique challenges that transcend the capabilities of a singular standard, unlike what the community has become accustomed with the success of the AM1.x standard for outdoor application. We aim at illustrating the pitfalls associated with a one-size-fits-all approach to standardisation, emphasising the necessity for a concerted and nuanced methodology tailored to the complexities of indoor energy utilisation, and particularly in the context of the various needs of the Internet of Things. Acknowledging the inherent variability in indoor illumination conditions, and using simple numerical modelling and real-life examples to illustrate how it influences the output of indoor cells, we advocate for a shift from conventional standards to comprehensive guidelines that will better accommodate and evaluate the diverse interplays between photovoltaic device, internet of things sensors, and illumination sources. Our proposed methodology is not merely a set of rules but a strategic framework for the community to build upon, inviting researchers and industry stakeholders to collaborate and establish a unified foundation for assessing the performance of photovoltaic devices indoors. By fostering a collective approach and steering clear of rigid standards, this viewpoint lays the groundwork for future studies to better assess the performance and usability of indoor photovoltaics, thus ensuring innovation, adaptability, and reliable analyses in this very fast evolving and increasingly relevant field.