# M13 Bacteriophage-Assisted Synergistic Optical Enhancement of Perovskite Quantum Dots
## 1 Introduction  
In recent years, there has been considerable interest in investigating the optical properties of various types of luminescent nanoparticles. Rare earth-based nanophosphosphors have garnered attention for their excellent luminescence and oxygen storage properties [1; 2; 3]. Transition metal oxides are notable for their intriguing magnetic and catalytic properties [4; 5; 6], and pyrochlores display a broad spectrum of optical properties [7; 8; 9]. However, among these diverse nanoparticle types, photoluminescence perovskite quantum dots (PQDs) have emerged as particularly significant due to their exceptional optical properties and potential for applications in optoelectronics [10; 11; 12; 13; 14]. This interest in PQDs stems primarily from their unique advantages over traditional luminescent materials. The high photoluminescence quantum yield of PQDs, low-cost synthesis, and compatibility with solution-processing techniques allow for the fabrication of flexible and large-area devices [15; 16; 17; 18; 19]. One of the key advantages of PQDs is their wavelength tunability, whichallows for the emission of light at various wavelengths [19; 20]. Moreover, the toxicity of PQDs can be managed by altering their surface chemistry, which helps reduce the release of toxic heavy metals [21; 22]. This feature enhances their appeal for a wide variety of applications, including displays [23], lighting [24], and even biomedical imaging and sensing [25; 26; 27]. Achieving high photoluminescence efficiency is crucial for unlocking the full potential of these materials in real-world applications. Increasing photoluminescence is frequently associated with enhanced material stability. By reducing non-radiative recombination pathways and enhancing the emissive properties of PQDs, their stability can be improved, leading to longer device lifetimes [28; 29; 30]. Furthermore, enhancing photoluminescence involves increasing the photoluminescence quantum yield (PLQY). A higher PLQY signifies a more efficient light emission, making perovskite quantum dots (PQDs) more practical for various applications [31; 32]. Researchers have pursued various strategies to enhance the photoluminescence efficiency of luminescent materials. Traditional approaches include co-encapsulating rare earth-doped nanoparticles [32; 33], coupling with plasmonic materials [34; 35], and surface functionalization of transition metal-doped solids [36; 37] or polarized molecules [38]. Although these methods can enhance optical and magnetic properties and introduce lattice defects, they have limitations, such as low efficiency, poor stability, and difficulty in precisely controlling the properties of the luminescent materials [39]. The emergence of perovskite quantum dots (PQDs) offers a promising avenue to overcome these challenges. To enhance the photoluminescence of PQDs, researchers have explored various techniques, including surface passivation [40; 41; 42], which involves coating the PQDs with a thin layer of organic or inorganic materials to minimize surface defects and trap states; ligand engineering [43; 44], which focuses on modifying ligands attached to the PQD surface; and defect control [45], a key method for customizing the electronic and optical properties of PQDs by manipulating their defects. One promising strategy is to couple the PQDs with biological molecules, such as proteins or peptides, which can act as templates or scaffolds for their growth and assembly [46]. This approach leverages the distinctive properties of biological molecules, including their capacity for self-assembly and specific ligand interaction, to direct the formation of well-defined PQD structures. By judiciously choosing the biological molecule and managing the coupling conditions [47; 48], researchers can exercise precise control over the size, shape, and arrangement of the PQDs, which results in customized electronic and optical properties.