Transparent sunlight conversion film based on carboxymethyl cellulose and carbon dots

• It’s the first time sunlight conversion property of carbon dots is discussed.
• The hydrogen bond is formed between the carbon dots and carboxymethyl cellulose.
• Furthermore, the mechanical properties of the composite film are improved.
• Finally, this film is expected to apply in agriculture for sunlight conversion.

Transparent sunlight conversion film based on carboxymethyl cellulose (CMC) and carbon dots (CDs) has been developed for the first time through dispersion of CDs in CMC aqueous solution. Due to the hydrogen bonds interaction, CMC can effectively absorb the CDs, whose surfaces are functionalized by lots of polar groups. The results from atomic force microscopy (AFM), scanning electron microscopy (SEM) confirm that the composite film possesses a homogeneous and compact structure. Besides, the CMC matrix neither competes for absorbing excitation light nor absorbs the emissions of CDs, which reserves the inherent optical properties of the individual CDs. The composite films can efficiently convert ultraviolet light to blue light. What’s more, the film is transparent and possesses excellent mechanical properties, expected to apply in the field of agricultural planting for sunlight conversion.