This study reports the using of boron-doped carbon quantum dots (B-CQDs), which can convert ultraviolet to blue light, as an additive in MAPbI3 based perovskite solar cells (PSCs) for improved photovoltaic performance. After a successful facile synthesis of B-CQDs, our work showed that the appropriate addition of B-CQDs (5% vol.) into MAPbI3 absorber layer can passivate the grain boundaries of perovskite crystals, improve the crystallinity and the grain sizes. Additionally, optical, and photovoltaic characteristics showed that the addition of B-CQDs can efficiently improve the charge transport properties and the hole extraction, while decreasing the recombination losses. In comparison to control device, power conversion efficiency (PCE) of champion device was increased from 10.4% to 12.7%. This approach of constructing inverted p-i-n PSCs with B-CQDs additives offers a simple way for the preparation of efficient and stable perovskite photovoltaics for future application.